Pro tip, put heatsink compound on the bottom of the ICM or it will fry out again on a 110 degree day. the metal thing it attaches to is a heatsink, therefore heatsink compound. had 3 fry out until I did this 6 years ago no more problems. other than driving a 20 year old car. 294k miles series 2

Thanks for the AWESOME INFO

I had the exact same issue on my 2008 grand prix. For the longest time i could not find the issue. I changed: spark plugs, wires, coils, ignition module, and PCV valve. Eventually after fixing a valve lifter issue the rough idle and misfire was fixed. Turns out the intake manifold gasket failed causing a small vacuum leak.

Electronics parts cleaner and some Dielectric grease to insulate the wires and ground. Coat that wire loom that connects to the ICM with Dielectric grease to insulate.

I’ve been having the same issue with my 07 Grand Prix for 6 months now, I initially thought it was transmission shudder but I’m chasing a misfire now.

You want to see 5000-8000 ohms. Not 5. Set multimeter to 20k ohms setting

I've got the Buick 3.8 series 3. Which I have heard a great Motors unless you get a lemon, and I have latched onto a lemon. This thing has a cyl 4 miss and I have triple and quadruple checked spark, fuel compression all good. Cylinder 4 is the one with the miss. While doing the last compression check I got the normal 150 lb that I always get, But the second time engine cranked, it started running and I checked the gauge with it running and compression was bouncing between 20-25 psi. A sluggish valve? What would cause compression to be Lost at higher RPMs but not cranking rpms? Lifter? Sticking valve? Gremlins?

turned out to be the intake gaskets?

check and dry your passenger front vss pigtail mine got wet and the car about went to junk yard= cleaned dried and purchased new pigtail - cleaning actually worked re-connected wires dry.it worked! got spare in glove box didnt need new but should do. o-ring prob needs new on connector vss. trust cheers

You have to use an even coat of "Heat Sink Grease" on the back of that ICM or it will fail prematurely

i replace the coil brain and mine fired up still runs rough i think its fuel pump now. stalls out while idled down at lights and stop and go traffic replace air sensors.

best part was the back round music 1- nice and quiet 2- the music good choice.

Same issue on my step sons car 08 GP... cylinder 5. I've never said I hated a 3800 until now. Plugs, plug wires, injectors still. I've tried 2 other ICMs, swapped packs around. I'm beyond lost

You would have benefited using a scanner that monitors each cylinder for misfires. If it's one cylinder compared to multiple cylinder misfire make diagnosing so much less complicated...

I had one and it was a spark plug so I changed all of them.

Did you figure it out? I'm having the exact same issue.

Did you ever get this figured out?

WHAT WAS THE FIXX????

Wat code did u have for misfire

It's the ECM... million percent

Nice regal i need a clean one, i have one right now for off roading

I just changed my Buick GS ignition coil module and fixed the misfire . Definitely recommend changing it

I have a 1999 grand prix and I have the same problems! I have replaced everything and cannot find why this car wants to run like crap!

03 Buick it was the 2 and 4 icm

3800 misfire causes 1. Ignition control module 2. Bad coil packs 3. Intake manifold gaskets- there are 2 4. Spark plug wires 5. Vacuum leaks from worn hoses 6. Stuck or bad lifter- caused by if you arent changing oil every 3-5k miles. Long oil changes intervals =have crud oil and oil sludge These engines are extremely easy to work on and to maintain. Their problems are from lazy owners not doing maintenance

I'm replacing the injectors and sparkplugs mine has a miss aswell I'm also getting my timing done

I have my work car 90’ Olds 88 and runs decent but has same issues. Misfire, engine light, sporadic stalls, I’ve thrown parts at it and still no luck. (I’m no mechanic at all)

Have the same issue but my cat is hollowed out.... My fuel pressure is good. I jus can't figure it out

The Door Chime sounded funny when you turned the car on I know why that’s because your girlfriends Grand Prix has an aftermarket radio

Should have taken off the coils from the ice first woukd been easier

its a coil

Spark plug wires not connected fully causes shutter at idle .. reconnect all the wires again..

I had the same issue on my 08 grand prix all I did while it's on is one by one unplug a spark wire from the coil and see if it sparks If 1 of the coil pack ain't giving you sparks then swap it with a working coil And if that still didn't work Thenswap out your ignorance module

Did you ever find the fix to this?

My brother has one there is a sensor connected to the gas pedal which you would have to get a new gas pedal prevents the car from making power

What? GM with issues? No way, never. Lol

NEVER fix a "girlfriend's" car. Cause she is NOT a permanent attachment to YOU. And when you find out she's got her fkboy that does NOTHING while your over here having headaches for 6 months chasing Her car problems while Mr. Fkboy is nice and comfortable NOT getting dirty and in between her Hoohaw.