Author Topic: hesitation during acceleration (Read 4408 times)

jrobie79 · « **on:** March 07, 2012, 08:07:46 AM »

so yesterday I was driving down the highway in 5th gear tonight, and I noticed when I went to pass someone and pushed it, there was almost a hesitation, kinda stuttered for a bit...only at WOT tho, it would still accelerate if I let off even just a tad

then today on the way to work happens in all gears, when I push it to get onto a highway and/or passing people, and sometimes its not even at WOT, just during acceleration and the check engine light pops on, but as soon as I lift my foot off the gas it goes out...definitely a huge loss of power and while the check engine light is on the car would barely accelerate if at all, kinda just stayed constant or even slowed down a little going uphill.

Thinking maybe one of the sensors or TPS? I dont think the fuel pump would cause the CEL to come on, no?

Wrench · « **Reply #1 on:** March 07, 2012, 08:27:40 AM »

That sucks... kind of tricky to give you a simple answer as to what could be wrong.

Basic things to check first:

Fuel pressure and volume
Ignition components
TPS
Main relay
O2 sensor

Run a can of Seafoam through it and see if it clears up.

jrobie79 · « **Reply #2 on:** March 07, 2012, 08:35:39 AM »

well the stomp test yielded 1234, which is a speedometer code, but that doesnt seem like it would cause any problems with the engine running properly

DesktopDave · « **Reply #3 on:** March 07, 2012, 10:56:05 AM »

Maybe a corroded VSS in the diff or the plug. They take a lot of abuse from salt spray...mine fails when it's really cold but the DME never sets that code.

I'm pretty sure it's an input to the DME. It's on pin 29 of the 1.3 DME according to this pinout (not sure about the M42 1.7 but they're pretty close). From what I've read it's for signal failure ten seconds or longer. Maybe the DME compensates for idle somehow...timing advance or fuel lean?

jrobie79 · « **Reply #4 on:** March 07, 2012, 12:06:43 PM »

well my speedometer sensor is disconnected, has been for a month, no other problems. I am going to connect it this weekend, but as its been disconnected for a month I dont see how the problems would arise now

mr ilia · « **Reply #5 on:** March 07, 2012, 03:19:49 PM »

Vacuum leak, possibly AFM. As stated before, run seafoam through the system, clean AFM, check for vacuum leaks.

jrobie79 · « **Reply #6 on:** March 08, 2012, 08:14:16 AM »

its not the TPS (replaced it with a known working one), and i cleaned my AFM, I think the fuel pump is giving out...it happened a lot more frequently today, and not just at WOT. As for vacuum leaks, I just did the under the intake mod, all the hoses have less than 5k on them and the connections are tight.

omererden · « **Reply #7 on:** April 18, 2012, 10:58:58 AM »

It could be the spark plug wires, it happened to me.

axisofjustice · « **Reply #8 on:** June 26, 2012, 02:13:58 AM »

Why do people always cop out and never post a resolution? The point in forums and free info is that you share your experience in return as to proliferate new info and help others down the road as you've been helped. Never can find a simple, "x part solved y problem by performing z procedure." Just take what you need and disappear. Sorry for the tirade but this is search dead-end number 5 and I don't want to start a thread for a common issue.

jrobie79 · « **Reply #9 on:** July 01, 2012, 10:16:12 PM »

it was the fuel pump...replaced it with a TRE performance one and no problems for the last 8K miles

axisofjustice · « **Reply #10 on:** July 01, 2012, 11:19:33 PM »

Awesome, thank you for replying. I appreciate it.