2004 GRAND PRIX MISFIRE MYSTERY

[@s7uidz]

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

[@spencer9005]

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.

[@sterlingwitherspoon5709]

WHAT WAS THE FIXX????

[@user-ng5fg6lh2d]

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.

[@Brian-fo8sh]

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.

[@dylano7242]

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

[@oldriver1827]

I believe that if the misfire is found at the coils or icm that part of the repair should be check and clean engine ground. A bad engine ground will over work these parts causing them to fail, dooming the replacement parts to early death.

[@headpainter1]

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?

[@concretechef9904]

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.

[@MacAutoDiag]

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

[@lowk3yo]

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

[@teaganroszell1732]

Try a compression test, might have a major leak

[@adamlaird5207]

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

[@davidkuhrt3657]

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...

[@LukeWaters]

absolutely lol, I do need to get a better scan tool to help with diagnostics, its definately on my list of tools to get

[@pawpatina]

turned out to be the intake gaskets?

[@ohbillytv179]

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

[@davidfrank6666]

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

[@kevinduder7237]

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

[@joshwhetstone1310]

It's the ECM... million percent

[@MugetsuDeath]

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

[@neonpeonu]

Did you ever get this figured out?

[@ellafindsout940]

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

[@LukeWaters]

I've been slowly messing with it again, changed battery cables, one seemed loose. Issue is still here lol I just told her to drive it till it dies

[@baylertolman9910]

I don't have a cat on my 06 and it runs better in my opinion

[@israel7294]

Wat code did u have for misfire

[@Ry77x]

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)

[@donprepstien1920]

Do a leak down test. The tester is like $75 tho. I went cheaper and got two broken testers in a row.

[@analogkid4557]

Vacuum leak at intake.

[@Ry77x]

@@analogkid4557 it was actually the coil pack exploded and leaked the “glue” stuff on the circuit board. When the car warmed up, the “glue” interferes with the electrical. I replaced and ended up selling the car shortly after I made this comment. I learned a dang lesson in that car and never again will I just throw parts/sensors at it. It was a good car. I’ll miss her lol

[@Jesusloves1971]

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!

[@SuperSportfan1]

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

[@LukeWaters]

swapped an icm after I stopped recording, issue persist lmfao idk whats up with this thing. Im wondering if the bad intake gaskets is the reason

[@SuperSportfan1]

Wow Luke sorry to hear that , your going to have to start throwing parts at that 3800 until it works . Wires plugs , maf sensor , fuel pressure regulator etc.... lol Could be an easier fix! Good luck and keep us posted in the videos. Love all the cars in your fleet .

[@Dat550go]

Change your Crank shaft sensor and ⚙️ gear.

[@genewilliams3810]

Thanks for the AWESOME INFO

[@fordsman7731]

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

[@Erasing]

Did you ever find the fix to this?

[@LukeWaters]

Yes! Clogged cat lol. Ran a gallon of lacquer thinner in the gas tank and it helped, didn't 100% fox it but made it drivable again

[@benkalinowski5834]

How many miles were on it

[@LukeWaters]

@@benkalinowski5834 240k

[@AndrewSmith-lm5uq]

Did the laq

[@AndrewSmith-lm5uq]

Did the lacquer thinner hurt the engine

[@calvindirkmaat]

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

[@calvindirkmaat]

03 grand prix with no com to the computer, 97 regal with a bad misfire and the engine blew

[@LukeWaters]

@@calvindirkmaat so you currently have an offraod regal?

[@jlb7125]

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

[@tristanlaster8056]

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

[@LukeWaters]

Right on, thanks for the input! The car has now since been sold, we traded up to a 2014 ford edge

[@skigdividerx4991]

Did it just sound like it was mising on all cylinders ?

[@enjoythesho1992]

​@@LukeWaters you traded down lol

[@rrboss33]

03 Buick it was the 2 and 4 icm

[@fordmustang98guy]

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

[@LukeWaters]

Its very loud and annoying tbh lol it drives me crazy!

[@fordmustang98guy]

@@LukeWaters how long has your girlfriend had her 2004 Grand Prix?

[@LukeWaters]

@@fordmustang98guy mayyyybbbbe 2 years lol, not very long

[@fordmustang98guy]

@@LukeWaters My 2002 Regal LS never left me on the side of the road never broke down ether other than a bad starter motor

[@fordmustang98guy]

@@LukeWaters any update on your Girlfriends 2004 Grand Prix?

[@luiscamargo779]

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

[@unkowntrooper1657]

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

[@andrewwarner8130]

its a coil

[@christianohms6672]

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

[@LukeWaters]

lol ever man! All of my gm cars now have some sort of issue (:

[@pitdawg6418]

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.

[@LukeWaters]

Brother who hurt you?!

[@BenjaminPerez-rv6db]

Replace the grank sensor and your problem will be gone

[@concretechef9904]

😢

[@MacAutoDiag]

These simps and young bucks ain't ready for such wisdom. Let them learn the hard way like billions of other men