Thread: Giving up on random misfire at idle

Originally Posted by gingerdude

Coolone you wouldn't happen to know which side the wiring loom you're talking about is on would you? Because honestly that is literally the last thing I think it could be. Something keeps saying CPS. It gets really bad after I have been on a long drive. I would imagine a failing CPS would produce these symptoms as it warms up.

No, the CPS is one thing, but is a long shot in my opinion and a last resort shotgun part at a problem kinda thing, roll of the dice so to say.

But the wire break in the loom was definitely the cause. Was intermittent just like yours and really went nuts tracking it down. Is the driver side where harness leaves PCM and is real close to the condenser. And again, was in my buddies paid for mechanics database, don't know they aem of the system he used, but is a commercial product which repair shops use. It nailed the cause... Lol and just to be clear this is just on the 3100 and not applicable to the 3800. Just get in there and make a real good visual inspection, if you see anything that doesn't look right, then look closer. And for the matter, it doesn't take much to open the loom and look too.

check the ICM harness connector. I have had one where one of the wires were pushed back not making contact properly.