'90 Bonne throws code 42, the ICM tests out fine, any suggestions?

Can you give us some more ifo? Is the engine not starting, stalling or just running crappy?

It does run,but not as responsive. It seems to run the worst cold (in open loop), sometimes have to two foot it to keep it running. Once in closed loop, the check engine light stays on but run better.

When was the last time the plugs & wires were changed? If it'* been awhile I'd pull the plugs & check them out. Keep track of which cylinder each plug comes from.

I will check them out and change them anyway

Code 42 can mean a bad ICM. Just because it passed those generic autozone tests doesn't mean the unit is good. I've heard accounts of good units failing and bad units passing.. and I also have experience with that. You really want to try swapping ICMs.

It could also be the timing chain jumped time, however I think usually you get a code 43 if that does happen [not sure].

The Bone stalled and this time wouldn't restart. I noticed that th ICM & Coil pack were melted together, so I ended up swapping out the ICM/Coil pack, even after it check out good when Napa tested ( just as opensourceguy stated). Car starts now but still throwing code, did a quick tune up with plugs and wires not knowing when it was done last. I finally diagnosed it to the ECM, went to the local salvage yard lucky enough to find a factory reconditioned ECM out of a '90 Lesabre, installed and car runs an idles smoother than it ever has. Thanks for the input.