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bout to give up

jtckf

New member
My sons car..
The engine cuts out every so often. At idle, it revs some on its own..
what I've done,
1. new plugs and wires ( which needed changed anyway 131K)
2. all new coils
3. new gas cap
4. the supercharger was rattleing, so we just changed the coupler..sound is gone now...coupler was deffinately worn

but now back to why is the engine cutting out..Any ideas????
 


Does it die while he is driving? Ever notice the tach dropping to 0 before it shuts off? Could be a crank position sensor. But I would start by removing and cleaning the MAF with approved cleaner and try that. Is the CEL on? What type of plugs did you put in?
 
I would look at the idle air control valve, and check the fuel pressure. Just and idle problem, or does the car surge while driving? Could start with iac the inexpensive, easy to replace. Incorrect fuel pressure would cause this to causing the iac to have incorrect readings. If the car surged while driving i would suspect a tps, but it sounds like you just have an idle problem. The crank position sensor will cause random stalls to, combine with vacuum leaks would cause a high idle. But i would start with the iac and fuel pressure. Hope this helps a little, there's always a few other things it could be.
 
what year is the car? and did you check for vac leaks yet. one may have broke when you did the coupler. or they break with no help too.
 
it also surges/cuts out while driving. RPMS don't drop to zero, but a couple hundred RPMs or so
just cleaned the MAF, with the CRC MAF cleaner
 


First, does it have any SES codes?

Unplug the MAF entirely with the car off. Start it up and let it idle for a minute then drive it. See if it does the same thing. If it is fine, then it is the MAF. (I've had this happen before even after cleaning the MAF)

Check and see how much vacuum you are pulling at idle. Should be 18-20 in/hg

Check your battery connections and all your grounds and ensure they are tight and have good connection.

Lastly, when was the fuel filter replaced last? Usually they only present issues at higher rpm with fuel starvation, but I've seen them cause issues throughout the range before.
 
I had similar issues to you and followed every tip on the forums. New maf, fuel filter, fuel pump, Changed the crank position sensor and even Went back to stock wires with new plugs! Nothing helped.

It turned out to be the plate underneath the coils (ignition control module). Had a spare in the garage and changed it out. Have not had a problem since!
 


many of those similar issues occur on cars where the cam/crank/ICM harness is improperly routed and it gets dragged into the AC clutch where it intermittently shorts to ground through the pulley bearing...ive seen dozens similar...
 
thanks everyone for your ideas...I've ordered a MAF, IAC and TPS for now ( since these seem to be the cheap ideas first)..they should be here Thurs. I'll install each one at a time and road test before I install the next one.. If all fails, at least I know they'll all be new. Then I'll try the Ignition Control Module...If thats not it, then time to bite the bullet and take it to the dealer...but first, I'll have to re-mortage the house..
 


No Luckyg, your issue is different.. And High octane, I cleaned the top of the plate real good before installing the new coils..The other parts are supposed to be here today. If they don't clear up the problem, I'll get a new Ignition control module. After that, I'm done. To the dealer it goes. Hate throwing money at it and it not being the problem. Glad they're all kinda cheap. At least the parts will be new and wont have to worry about them for awhile
 
Well my issue was a progression of my MAP sensor failing more and more until I bit the bullet and took it to the dealership to get scanned. Might be something worth looking into.
 
well to the dealer it goes...now its having a hard time starting..
1, new gas cap
2. new idle air control valve
3. new MAF sensor
4. new coils
5. new plugs and wires
6. new TPS
Cleaned the ignition control module, rechecked the plugs...now throwing an evac code. Time for the dealer to smoke it. I give up trying to find the problem...
The MAF sensor did clear up the part where it cuts out...service engine light on...Damn car is really starting to piss me off. Never had this problem on my old car, 98 Buick Reagl GS...the Grand Prix is the kids car...guess this is why Buick is still selling cars and Pontiac has gone by the wayside...too bad too, I REALLY LIKE this Grand Prix
 
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