Perpetual Misfire

[Squilliam]

Hey guys. Hopefully I can get a little guidance on this issue. Apart from the reman'ed motor developing piston slap (old motor didnt do it), the car has been mechanically strong since the motor swap back in December. But, it seems as if I've been fighting an uphill battle with a mysterious misfire issue that only occurs under light throttle. Pretty much everything has been replaced at least once. The wires have been replaced twice (Napa Beldins right now) the plugs 3x (Copper AC's, then Autolite 104s, then back to the copper AC's) and an ICM and all 3 towers from a 2004 Bonnie. It seems like anytime I do something, the car will run fine for a day or two, then slowly degrades. Its gotten to the point where I'll start off after letting the car sit for a few hours and it will completely cut out, lights will dim and my volts will bottom out, then come right back. Under light throttle in any gear brings about fits of seizures that mimics TC shudder. I really dont know what else to look at. Any thought would be great for my sanity. Thanks

-Bill

[MattStrike]

Check your main grounds first, then make sure the main power cables aren't shorting out on something. Also inspect the engine harness to the pcm, make sure no critters have been chewing on things. The next thing I'd rule out is the MAF sensor and TPS, then the PCM last. I usually go with a junkyard PCM from the same engine/trans combo to save money.