M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Electrical => Topic started by: ohnoes on January 20, 2007, 12:32:25 PM
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Hey all,
So I posted this on Bf.C, but I figured more specifically, posting on the M42-only forum might be a good idea, too, since y'all know the M42-specific glitches, tips, and tricks.
So for a couple months, I have been experiencing a sometimes-severe bucking and hesitation problem, especially when it's wet outside, and I didn't know what it was caused by, but it was certainly kinda scary to be accelerating on the main thoroughfare and be bucking about like a rodeo horse.
Usually, while and only while this was happening, the CEL would come on. Then it would promptly disappear when the engine combusted normally again, usually after a second or two.
As I was a car noob at the time, and still am, my mechanic apparently knew the gas pedal-diagnostic test, and he said it was throwing two codes: O2 sensor, and camshaft position sensor (IIRC). But then he said it wasn't the O2 sensor code, just the camshaft position sensor code, that he had misinterpreted the computer.
Then the CEL went away while driving, but came back while simply sitting at idle, i.e. traffic lights and while waiting to pick someone up, etc.! When I pressed the gas above 2,000 RPM, it would go away, then come back about 15 seconds later. Another mechanic and I discovered that the crankcase vacuum hose was completely disconnected!!! So I bought the hose, connected it, and all was fine for a while.
Then I started having this bucking and hesitating problem again, and we replaced the camshaft position sensor, as per the code it would throw while I experienced the problem--1244.
Now the car will occasionally, but less often, buck, and just five days ago it stalled on me completely while driving at a low speed in a residential neighborhood! I pulled it over, and it WOULD NOT start. It seemed to crank and spark (well, I didn't check spark...) and even SORT OF started, but then it would get bogged down in what sounded like fuel and simply die.
The engine threw the SAME, CAMSHAFT POSITION SENSOR code that we had BEFORE replacing it, when the car stalled like this.
I left it there overnight and my mechanic towed it the next morning.
Guess what? He said it was PERFECTLY NORMAL and drove it around all day on various errands.
This car is so frustrating. What could it be that is causing a CAMSHAFT POSITION SENSOR code but yet we replaced that sensor???
I have read somewhere that actually, a faulty crankshaft position sensor might cause the camshaft position sensor code, since they are fairly similar sensors, and both Hall Effect, IIRC...? Anyone know whether or not this is true?
ANY help whatsoever would be appreciated. I need to figure this out ASAP!
Thanks in advance!
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Well, I ran Seafoam through my gas tank yesterday and all I can say is the car is running better than ever!!! Much smoother, likes to rev more, and is generally much better. I'm not sure how long it will LAST, but it leads me to believe that maybe it was a stuck-open injector that was throwing off the timing of the combustion cycle, which in turn messed up the camshaft position sensor signal, which in turn threw a code and caused misfires.
Sound plausible?
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Please... can anyone help?
The car stalled on me today while turning onto my street. Was shifting into second and it just died. Finally started back up again after about a half dozen times. Died again when I got to my house--right in front of my driveway, blocking our other cars. Had to let it roll back (luckily, there is a hill; thank god for gravity) and press the brakes pretty hard to stop it in front of my house 'cause of the snow. This is simply unacceptable.
What could it be? I am still getting the camshaft position sensor code!!!
If this helps, when I got it back started, it was running perfectly fine. BUT, when I floor the gas from idle, EVERY SINGLE TIME, the CEL comes on and it misfires, then the CEL goes off, and it comes back to idle. But when it comes back to idle, it goes kinda low and the car shakes/rumbles a little bit, and then it resumes normal idling.
ANY SUGGESTIONS WOULD BE SO APPRECIATED. I CANNOT DRIVE MY CAR UNTIL I FIX THIS PROBLEM.
Thanks!!!!!!
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could be either the ecu, or did you check for a loose connection where the cam sensor plugs in. there is a wiring harness there, and it could have some loose connections developed in it over the past number of years.
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Thanks for your response, dude! Much appreciated.
Hmm, no, I didn't check for a loose connection there, but doesn't it just stick in and it's secured by a bolt? This is a brand new sensor, new wire, etc.
How would I check the ECU? Could it also be the DME?
Also, I've read that a crankshaft position sensor can cause a camshaft position sensor code. Any clue if this is indeed true?
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I would start with inspecting all hoses for leaks. While it's running normally, spray WD-40 on the vacuum and pollution hoses. This will change the speed of the idle as the leak is temporarily plugged by the WD-40. Check all of the wires and connectors for cracked insulation, places where they could rub on the motor and ground, loose plugs, etc. These are 15+ year old cars and a lot of weird stuff can happen that is real obvious once you find it. Rubber and vinyl under the hood go through a gazillion heat cycles in 15 years.
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So you think vacuum leaks could be causing the camshaft position sensor code to be thrown?
Worth a looksie, I suppose. I don't even know where most of the vacuum hoses are. There seem to be so many beneath the actual engine and stuff; or maybe those are other types of hoses. And aren't there more beneath the intake manifold and other hard-to-access places?
Seems like there's dozens of hoses down there... this is gonna be tricky.
Thanks for the responses thus far!!! Much appreciated again.
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and/or wiring. I had a temp gauge wire short intermittently once. There is also wiring to the sensors.
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and/or wiring. I had a temp gauge wire short intermittently once. There is also wiring to the sensors.
Explain? Like where is this wiring, and how would I go about testing all the wiring continuity. Sounds like a huge/tedious job!
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i did not mean check for a loose connection where the sensor bolts in, but where it plugs in on the other end. that wiring harness is mounted to the engine and gets a lot of vibrations, chances are good that there is a loose connection there.
out of curriosity does anyone know what makes the CEL flash a cam sensor code? where does it get its information from to decided that its a cam sensor?
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i did not mean check for a loose connection where the sensor bolts in, but where it plugs in on the other end. that wiring harness is mounted to the engine and gets a lot of vibrations, chances are good that there is a loose connection there.
Ah, I see what you're saying. But we replaced that sensor. You're saying that a) the previous sensor may not have been bad, and b) it may just be a loose connection?
I tried to wiggle the sensor, and it wiggled only a tiny bit, but not enough to make me think it is losing electrical contact. Maybe it is, though. How would I tell???
I also tried to wiggle the connectors (there are two, it seems??? Which is kinda odd, since there is only one sensor...) on what I presume is the DME--that long, black box running along/partially underneath the engine block (?). They wiggled substantially.
I wanted to try disconnecting the connectors on the DME and see if that would replicate the problem every time. If so, well folks, we have our answer. :D But alas, I didn't want to break anything so I didn't pull too hard to get 'em out. There might be a bolt or something I'm not seeing.
BTW, my car was running perfect in the neighborhood until it got fully warmed up. Then, as I was making a right-hand turn at a stop sign up an incline, and pressed the gas rather hard, the CEL flashed and the engine misfired, but DID NOT stall. When it came back to idle, it rumbled and came too a low idle, then went back up to normal idle speed.
I can replicate the CEL/misfire almost every time as follows:
1) Idle, fully warmed-up engine (must be at idle). I have not tried this test with a cold engine; I suppose I should. I have a feeling it will do the same thing.
2) Press gas quickly and substantially ONCE so that revs go above 1,000 RPM but below about 2,500 RPM. A slight tap will not produce the desired effect.
3) CEL usually flashes and car usually misfires.
4) When engine comes back to idle, it goes to about 550 RPM (lower than it should), car rumbles, wants to stall or something, but catches itself virtually every time.
5) Conduct gas pedal OBDI diagnostic.
6) CEL flashes 1244, signifying "camshaft position sensor."
I have about a 60-70% "success" rate in replicating the problem with the above process.
Does it still sound like a camshaft position sensor?
out of curriosity does anyone know what makes the CEL flash a cam sensor code? where does it get its information from to decided that its a cam sensor?
This is what I want to know, too!
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UPDATE:
The car is sitting at the $tealership right now. The technician showed me that the computer (special dealership computer) is only detecting that ONE fault--camshaft "pulse generator," as they call it.
He told me he can't test it because it's not an OEM part. I ordered it from Pelican Parts, and it's manufactured by Facet, which IIRC, is a German brand. But he's saying he can't even test the sensor because it's not OEM. Anyone know if this is true? Don't see how it could be, but meh...
So basically he's implying that I have to spend $130 to buy another one of these damn sensors from the dealer and have him install it, and hope the problem goes away. If it doesn't, he said it might be a vacuum leak, or coils or something.
I just hope he can figure it out. I'm not paying these "experts" $115/hr for nothing.
What do you guys think?
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uhh... the sensor would have to be the same as OEM otherwise it wouldn't work on the car... so if he can't test it its not the right sensor for the car... the computer wont adapt to other sensors. Basically either you got the wrong part and some how it plugged in, or the mechanic is so full of shit its coming out his mouth.
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uhh... the sensor would have to be the same as OEM otherwise it wouldn't work on the car... so if he can't test it its not the right sensor for the car... the computer wont adapt to other sensors. Basically either you got the wrong part and some how it plugged in, or the mechanic is so full of shit its coming out his mouth.
He said because it's not genuine BMW stuff, they can't do proper tests on it because they don't know its specs. I sniffed BS, too, but I couldn't imagine hearing blatant BS from a STEP-certified, BMW veteran mechanic as this guy seemed to be.
I called Pelican Parts, either way, and if they allow me to return the sensor, which they probably won't unless it's certifiably defective, as per their return policy, it will only run me an extra $50 to get the genuine BMW one, which the dealer is obsessing over.
Total parts and labor for this sensor at the dealer: $230.
Ridiculous, but meh.
And you know what they want for control arms and control arm bushings, with parts and labor? $900. WTF?!!!?! Needless to say, I won't be paying that. They want me to also do sway bar links and tie rod assemblies, as they say these can easily contribute to severe braking vibrations, which I have. But I just got brand new brake pads and rotors, so maybe the rotors are warped...
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These sensors is quite sensitive when gap between cam tooth and sensor is not right. This is magnetic pickup sensor. Try google to finde some aftermaket ecu manual for correct gap. Messure yours. I had the same problems, my engine was working event without it, but the power was less than it should be, I replaced the o ring with new and fault disappeared :)
Good luck..
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These sensors is quite sensitive when gap between cam tooth and sensor is not right. This is magnetic pickup sensor. Try google to finde some aftermaket ecu manual for correct gap. Messure yours. I had the same problems, my engine was working event without it, but the power was less than it should be, I replaced the o ring with new and fault disappeared :)
Good luck..
Hmm, thanks for the tip. I will assume the BMW tech will install the new sensor correctly when he gets it. At this point, the matter is beyond my control, since the car is at the dealer right now.
New sensor should be overnighted and thus here tomorrow. I will give you guys an update tomorrow.
BTW, Pelican Parts is being cool and letting me return the sensor, albeit with a 15% restocking fee. :)
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Alright, so an update.
More bad news. The car threw the same code even after replacing the sensor! So that's two perfectly good sensors down the drain--and $230 for the new sensor + labor at the dealer.
I knew that mechanic didn't know what he was talking about. But apparently he's one of the older guys so people don't want to subvert his decisions or sidestep him. Kinda sucks.
So he wants me to authorize two more hours of labor to "diagnose" the problem. I'm not going to have that crap. Even if they diagnose it, he told me the DME or wiring harness could be bad--each of those is $800+.
The car, however, ran perfectly on our test drive after the new camshaft position sensor. He told me the code only came up right after he replaced the sensor and disconnected the battery. Is it possible the computer just takes a while to completely reset itself? Because the car, again, drove perfectly on the test-drive. And I was pushing it pretty hard. No stuttering, no stalling, no hesitation, no misfires.
One of the newer techs (he was formerly working for Mercedes) overheard my problem and privately suggested that the wire may be intermittently shorting out or chafing on some metal, or just grounding. He said the easiest thing to do would be to simply wire the sensor directly from the engine to the DME and skip an unknown variable, the harness. But he said he didn't know if the dealer policies would allow that, etc., and it's not his "ticket," so he can't help me.
The original guy I was using didn't seem to think that was a good idea, but I don't lend him much credibility now, what with all this money wasted and his opinion that ONLY Genuine BMW parts should be used--NO EXCEPTION. Moronic, IMO.
So any of your opinions would be greatly appreciated!!! This car is a basketcase...
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If your still getting the code and it's running good then keep running it for a while then do the code stomp.
If the code comes back then disconnect the battery for a few minutes then reconnect and drive .then check code .
Someone correct me if I'm wrong but I believe the ecu stores the codes. That's why you don't start the car to get the codes because they are stored in the ecu.
Please someone tell me if I'm wrong but I think that's the way it works .
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I will do this, thanks for the advice. However, I have a certain feeling that the problem isn't gone--that today was just one of those days where it ran good. :(
I'll let you guys in know in the next couple days if the problem reasserts itself.
Thanks a lot for your help... you guys are great!
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i had a feeling it was a shitty connection, and its going to be right where they plugged the new sensor in.
to the ecu question, yes its stored in the ecu, and disconecting the batter will erase any stored codes.
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i had a feeling it was a shitty connection, and its going to be right where they plugged the new sensor in.
to the ecu question, yes its stored in the ecu, and disconecting the batter will erase any stored codes.
You mean on the ignition wiring harness, or on the engine itself where the actual sensor is?
Strange. The car ran perfectly for the 20 or 25 minutes I drove it today, but the code is still being stored in the ECU... I did the stomp test and got it. :confused:
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unplug the battery, then plug it back in and it will erase the code. it will be stored forever unless you do tht.
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unplug the battery, then plug it back in and it will erase the code. it will be stored forever unless you do tht.
Yep, we removed the ground wire from the battery and then plugged it back in after ~ 2 minutes.
Any more suggestions would be appreciated...
I am going to drive the car today in the wet since it is snowing/raining and hope the problem doesn't rear its ugly head. It tends to do it exponentially more whne it's wet outside...
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I was having the exact same problem tonight, what I noticed is my standalone stopped picking up the cam sensor, and the engine died, but after beeing dead for a few seconds I was able to start it up real and it ran for a few minutes,
I think the first action should be to check the resistance in all the wires from the sensor plug to the ecu to make sure that they are not at fault somewhere,
then I´d say checking the sensor spacing is up to spec( I´m sure the closer the better) .
if those things are fine definitly the sensor is at fault
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Gunni, thanks for the suggestions. Yes, I bet there is occasional chafing/shorting out of the wire or something. But weirdly, the problem has not reasserted itself since I replaced the sensor! However, the code is still stored in the computer. The CEL doesn't come on, but the pedal stomp diagnostic test still spits out that darn code.
I will see if I can check the wiring. If it's not that, I don't know what it is.
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In the meantime, I suggest finding a new mechanic. This one is throwing you so much BS its not even cool. I personally dealt with people like this when I was the IT guy at my old job, people would pretend like they knew how to fix a computer problem... If they knew how to fix it why are they giving it to me to fix in the first place? Anyways try having that other guy that overheard you work on your car would be a better idea if anything, from what I have read he actually knows his stuff and its just a matter of what he's allowed to do to diagnose the problem.
At this point I'm purely guessing on how to fix the problems since I have no idea how this sensor is wired or even where the hell it is in the first place.
I have no clue about the ambient temps the car is stored/parked in when it just happens to work flawlessly, and when its pure shiz. Does the car run like crap just when it sits in the cold for a while and better when its sat in a warm garage or something? (Or vice-versa.) If this is the case then something is shrinking or enlarging just enough to create a problem.
As for the wiring maybe (now remember I have no idea what this thing is or where its located, even less about how its wired) if the sensor connects to another wire try replacing the wire farther up just to see if there is a short somewhere. Inspect all contacts for corrosion or any other thing that kills performance. Securing the wire in a way where it rubs other components the least is also a good idea.
Getting back to my original thought about shrinking and enlarging, do you have a pic where you are spraying the Seafoam? There could be something mechanically there that is causing the problem. (Whether it be a teeny tiny hole or a crack.)
Remember I have no idea what the hell I'm talking about besides the general electrical/mechanical tips I've given, the other guys here will definately know more than I do since I'm still a 318is newbie.
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In the meantime, I suggest finding a new mechanic. This one is throwing you so much BS its not even cool. I personally dealt with people like this when I was the IT guy at my old job, people would pretend like they knew how to fix a computer problem... If they knew how to fix it why are they giving it to me to fix in the first place? Anyways try having that other guy that overheard you work on your car would be a better idea if anything, from what I have read he actually knows his stuff and its just a matter of what he's allowed to do to diagnose the problem.
First off, thanks for your response. You seem to be a new member, too. We're both learning. :D
Yeah, well, the sad part is he's an official BMW dealer mechanic, which really disillusions me. I thought dealers were very selective with their hiring process and stuff, and that they were the "be all, end all" when it came to BMW maintenance and issues. They certainly don't seem like it now!
At this point I'm purely guessing on how to fix the problems since I have no idea how this sensor is wired or even where the hell it is in the first place.
I have no clue about the ambient temps the car is stored/parked in when it just happens to work flawlessly, and when its pure shiz. Does the car run like crap just when it sits in the cold for a while and better when its sat in a warm garage or something? (Or vice-versa.) If this is the case then something is shrinking or enlarging just enough to create a problem.
As for the wiring maybe (now remember I have no idea what this thing is or where its located, even less about how its wired) if the sensor connects to another wire try replacing the wire farther up just to see if there is a short somewhere. Inspect all contacts for corrosion or any other thing that kills performance. Securing the wire in a way where it rubs other components the least is also a good idea.
Getting back to my original thought about shrinking and enlarging, do you have a pic where you are spraying the Seafoam? There could be something mechanically there that is causing the problem. (Whether it be a teeny tiny hole or a crack.)
Remember I have no idea what the hell I'm talking about besides the general electrical/mechanical tips I've given, the other guys here will definately know more than I do since I'm still a 318is newbie.
Here is the RealOEM diagram of the sensor: http://realoem.com/bmw/showparts.do?model=AJ93&mospid=47318&btnr=11_2683&hg=11&fg=10&hl=19
However, the diagram isn't exactly right, for some reason: it would appear from that diagram that the sensor end just terminates right there, but that is physically impossible. There is nowhere for it to terminate in that area. Instead, it goes all the way down to the ignition wiring harness, which I believe in turn connects to the ECU.
That other mechanic suggested to me that we skip the wiring harness to eliminate a variable and wire the sensor DIRECTLY to the ECU. If these symptoms happen again, I am inclined to go forward with that plan.
It is part # 6, "Trigger Contact." The BMW dealer mechanic checked out that wire from the sensor itself to the harness, but NOT from the harness to the ECU. So the harness-to-ECU wire could be shorting out/chafing sometimes or something. I'm really not sure.
I poured Seafoam only in the gas tank, and once before that in the crankcase (oil filler cap). It seemed to really unclog the injectors, but it did NOT solve the stalling problem.
However, as I mentioned before, I have driven the car about 20 minutes per day average for the past three or four days, and it hasn't acted up ONCE!
Maybe it does have to do with the warmer temperatures, although I'm more inclined to think it's related to humidity and moisture. At least in the past, it's acted up more in the early mornings (dawn) when it was a bit wet from dew and other moisture. That's when most of the stalling and stuff has occurred.
Thanks again! I will do some research on RealOEM and see if I can't find out where the ECU connects to the ignition wiring harness!
Look forward to more suggestions.
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Keep an eye on the engine temp gauge in the car just to see if it starts acting up when it reaches a certain temperature. Adding to my thermal expansion part I initially wrote the engine itself is also a major factor since engines obviously run hotter than ambient temperatures.
With that another idea struck me, there is the possibility of something in the fuel system that is sticking which prevents enough fuel getting to the engine. It did seem to work better in different environments, including when you added Seafoam. Its been a while since I even cracked open an engine (the only experience I have is with small engines) so I'm most likely wrong with this one... Maybe check these items for proper tightening/clogging/sticking? It'll be a lot of work so keeping an eye out for other parts that need replacing is a good idea.
http://www.m3racing.com/graphics/parts/5MM_valve_stem_kit.jpg
GET A NEW MECHANIC BEFORE EVEN THINKING ABOUT THIS .
There are just too many possibilities but as I mentioned it just doesn't seem like a wiring problem... Now for today's weather. We're in for a heavy downpour of WTF followed by a high pressure system of BS. :rolleyes:
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Keep an eye on the engine temp gauge in the car just to see if it starts acting up when it reaches a certain temperature. Adding to my thermal expansion part I initially wrote the engine itself is also a major factor since engines obviously run hotter than ambient temperatures.
With that another idea struck me, there is the possibility of something in the fuel system that is sticking which prevents enough fuel getting to the engine. It did seem to work better in different environments, including when you added Seafoam. Its been a while since I even cracked open an engine (the only experience I have is with small engines) so I'm most likely wrong with this one... Maybe check these items for proper tightening/clogging/sticking? It'll be a lot of work so keeping an eye out for other parts that need replacing is a good idea.
http://www.m3racing.com/graphics/parts/5MM_valve_stem_kit.jpg
Hmm, you think the valves are sticking or something? Would that really cause a camshaft position sensor code though?
I'm not sure if there is a temperature correlation so much as an ambient humidity correlation. I really can't establish a correlation right now. It's just too intermittent and unpredictable. :confused:
GET A NEW MECHANIC BEFORE EVEN THINKING ABOUT THIS .
There are just too many possibilities but as I mentioned it just doesn't seem like a wiring problem... Now for today's weather. We're in for a heavy downpour of WTF followed by a high pressure system of BS. :rolleyes:
Hahaha. LOL. So true. That one guy at the dealer was full of BS. I need to find someone better...
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thats how dealers roll, try and screw the average person as much as possible until their ass is sore enough that they give in and buy a new car.
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I'm going to call this one fixed. I picked up this car a month ago, threw another ECU at it, (thanks Alpine003!) and haven't had even a hiccup in 2 weeks (maybe 10 trips, 15-20 starts in that time). :cool:
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I'm going to call this one fixed. I picked up this car a month ago, threw another ECU at it, (thanks Alpine003!) and haven't had even a hiccup in 2 weeks (maybe 10 trips, 15-20 starts in that time). :cool:
Yeee haa ,
mystery solved
thanks for letting us know
I wonder how often the ECU is the culprit in these rough running issues ???