So my car has developed a miss and stumble in low rpms under load. It's an M6 and the miss is noticeable most below 3000rpm. I've done the search and have come up with tests to do for heat related problems, like the ICM, or coil. The problem was there before it was fully warmed up, it had been running 3-5 minutes, temp barely over 100, and it started missing. Do i still do these heat tests? What else do I look for? It has newer plugs and wires. AcDelco platinum tip plugs, ACCELL 8mm wires.

I think that doing these test would be pointless though, its only under load, sitting at idle it is not noticeable... One I'd start driving it to test it, it would warm up anything else really fast.

What do I start with? What could be the problem? Help is appreciated. I'm lost on this one . Thanks

 

anyone?

I was driving it tonight and the miss was most noticeable in 3rd gear below 3000 rpm..

anyone have any thoughts?

 

with those headers, I would check to see if one of my plug wires has been burned through, especially since you say you have the problem on startup. That would be my best guess.

 

A good way to test this is to drive the car normally and then upshift about two gears sometime during the drive. It should be smooth as glass(although straining a bit). If the car starts shaking really violently, then I bet its those plug wires. The same thing was happening to my car when I bought it.

 

thank you... i will have to try this tomorrow sometime. It's kind of strange, sometimes it will run fine, others, well most of the time it has the skip and miss. but not all the time.

thanks though and i will try this, hopefully it won't die on me... already done that! (with clutch in it died)

thanks again

rob-