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Ok need some help it's been awhile since I've had any trouble but I was having a misfire issue did some looking and found coil for 1&3 not firing went got a all new coils still misfiring tested icm it tested fine twice what controls my coils other than icm

ICM testers are a joke, don't trust them. I'd try another ICM if you can find one. Don't get an aftermarket, used OEM is best.

I'd replace the coil with an OEM from a u-pull yard. I've purchased two aftermarket coils and both were bad in about 3 months. I went to a "cash n carry" pull it yourself yard and purchased an ICM with coils for about $30, and it's been working fine for about 6 months now. I've seen this all over this sight. Strange, but used OEM parts seem to be much more reliable than new OEM parts.

Still have the misfire on the same cylinders?

Either way, try to find some factory parts.

I'll have to get up to a yard over the weekend no money til tomorrow and I don't wanna drive it on four cylinders

A lot of the people that looked at it said may be wiring issue but I just bought one from haro not too long ago and I re wrapped the whole thing so I know the wires are good could a bad alternator do it I mean I doubt it but never know... Just don't understand why other coils are working and coil for 1&4 isn't * I realize I put 1&3 silly me

Hi, check out this site ......http://easyautodiagnostics.com/gm/3.8L/ ... sor-test-1

That's nice but the car starts and only one coil isn't working how would I test that I've got schematics and there should be no reason why a single coil shouldn't work they run off a single circuit... ign feed in and spar reference out I'm a technician and this has got me a little baffled fuses are fine for pcm ign and all ign fuses... Wire schematics show ign feed as port P 839 pink/black wire and spark reference out is port C 647 light blue/black wire I wish I could find gm tech schematics then I could really pick the brain on this cause the only other things that may connect are fuel control and cam sensor I pray it's the icm cause this is a nightmare for me right now

I'm probably over-simplifying this but here's what I'd do.....take the coil associated with the mis-fire and swap it with one of the other coils. Check to see what's mis-firing. If the same cylinders are mis-firing, it's a problem with that location in the ICM, if the misfire is now on the cylinders associated with the new location of the coil in question, then it's the coil. Also, are wires and plugs known to be good?
Hope this helps.

I actual don't think I did that but that makes sense and will a NA Grand Prix icm work or does it have to be from a SC car

Well it was the icm pulled one from a gtp but it worked

GREAT! Glad you got it figured out! Great sense of accomplishment huh?

Yeah wouldn't have figured it out without you guys help now to figure out why system is running to lean

harofreak00 wrote:ICM testers are a joke, don't trust them. I'd try another ICM if you can find one. Don't get an aftermarket, used OEM is best.

Definitely agree. After working for autozone all of their testers suck. Icm, alternator other sensors etc. Same as any other parts store they aren't able to fully duplicate an on vehicle test.

its either the coils or the ICM... its pretty simple with the 3800 engine. Glad you figured it out My friend Bonnie had a coil blow...and he was broke..so i said just buy one coil..and replace and test. sure enough the middle coil was bad... now he is good. NEVER EVER BUY AFTERMARKET CHINA JUNK parts FOR THESE CARS... i cant stress it enuff. I went through the cheapo ebay parts..and ever one of them either didnt work or failed in 3 months.... your best bet for parts is the Junk Yard. Cheaper and 10 times better.

Ended up being the ICM