I'm still having some misfire problems underload. I thought it was my opti but i guess i am wrong. I have replaced plugs, wires, coil, and now a brand new opti and the problem is still there.

Is it possible that that lil module on the coil could cause a problem? Or maybe its just a bad coil? i got it from autozone so who knows maybe ill get a GM one but i really dont feel like pluggin and playin hopin someone can help a lil.

I will also pull out my plugs and check those... it was taken in before and they came up with 4 and 5 cylinder were misfirin bad. Dyno'd and the thing barely would climb from 1500 it was misfiring so bad. Just lookin to get my problem fixed. Thanks guys

 

almost everyone who i know thats had that autozone coil has had problems with it

 

It's probably not the ICM or the coil since it is occurring on the same cylinders. Hook an inductive timing light to the plugs in question and see if you see a misfire in the light pattern. If not, it's time to look else where for your problem.

2 things to try would be to switch injectors from a known good cylinder and the other is do a leakdown test and compression test.