M42 idle issue. help!

[iamcreepingdeath]

Had the same problem, traced it to the flapper in the MAF sticking.  Cleaned and lubricated it and the car idles perfect. Hope this helps.

Aloha

i'll try this.  But did the problem happen to you only when the car was cold?

[///m42 sport]

Ok I might try replacing the fuel filter

[///m42 sport]

op any updates?

[monty23psk]

Not sure if you have done this, but do the stomp test to see if you have a leak or bad sensor.

[///m42 sport]

I just tried the stomp test. I believe the code was 1444.  I interpreted the first long blink as the restart of the cycle.

[monty23psk]

So that means everything is ok for the most part. Narrowing this can be hard. First thing is to borrow an ECU from a working car. I have heard this can cause the issue you are having and it can be sporadic. Something you can visually inspect it and see some bad solders.

[///m42 sport]

went out and put some chevron with techron injection cleaner today.  Gonna see if that makes a difference.

[///m42 sport]

I drove around a little today.  The injection cleaner seems to have helped a little.  I feel the throttle response is almost back to normal.  The idle pretty level now.  Its weird that the engine still shakes a little.  I changed the cat with a "newer" one today.  will see if this will change improve things

[iamcreepingdeath]

no updates on my end.  Still runs like crap when cold, actually doesn't idle at all, you have to hold the rpms with the gas pedal.

[Systema]

Bringing this thread back to life, because I have a similar problem. My car seems to run fine starting cold (like, sitting all night in 10* weather cold), but it starts to run like crap as it gets up to operating temp. It misses and bleeds off power under constant throttle, and idles really low. Once it's at operating temp, it runs fine except for a lumpy idle.

Any updates OP? I've ordered a coolant temp sensor, but it'd be cool to see if you figured out a fix.

[BlueBMW]

I'll assume you have checked the little wire that is supposed to be unplugged as referenced in the other thread about hot running problems?

Bringing this thread back to life, because I have a similar problem. My car seems to run fine starting cold (like, sitting all night in 10* weather cold), but it starts to run like crap as it gets up to operating temp. It misses and bleeds off power under constant throttle, and idles really low. Once it's at operating temp, it runs fine except for a lumpy idle.

Any updates OP? I've ordered a coolant temp sensor, but it'd be cool to see if you figured out a fix.

[Systema]

Yup, I tried that. No improvement, unfortunately. The wire was where it was supposed to be for a US Cat car.

[BlueBMW]

How are your hoses under the intake?  Have they been replaced or modified?  Maybe there's a hard to find major vacuum leak somewhere under there.

[Systema]

As far as I can tell, all of the vacuum lines are fine. I did the mess under the intake hose delete a while back, and replaced everything I could. I'm pretty sure it's something related to a sensor somewhere, because the problem really only occurs at certain engine temps. I was thinking about cutting off my cat, since I don't have emissions to worry about where I live, and I have a feeling that the problem has something to do with it for some reason.

[dwtaylorpdx]

I bought my O2 from a local mainline parts house, it came in another brands box but inside was a nice shiny Bosche O2 with the exact same markings as the used one I took out.
it was about 90 bucks.

Dave