98 Grand Am Stalling Problem

Gas filter.

Check and / or replace the coolant temp sensor. Check the connections to make sure they are sound.

Steve B.

check the fuel pressure.

No Mr. Wong, that is "wong". You check the "basics" first, which he is doing. He just forgot/didn't know a few things to do/check. Once you've eliminated the basics, and a problem is still there, you can check the codes if you want, but they will be meaningless! Someone could have un-hooked sensors, pulled plug wires, etc. to see if the problem changes/goes away. Of course that will set a code, which is worthless. You need to clear the codes, then drive the car through various conditions, then check for codes and diagnosis/repair accordingly. If there are no codes, then you'll want check "real time data" and see what ain't doin what when it possda.

I had it scanned for fault codes. Their were none.

I have replaced the coolant temperature sensor, the spark plugs, the Idle Air Control motor, and the fuel filter.

To review....it stalls a couple of times a week. 15 % of the time it is after it was started cold and put into gear. 85 % of the time the engine is warm...perhaps having driven 10-15 minutes and sitting at a traffic light...it stalls on its own...or it is turned off after a few minutes of driving...say to run into a store...when it is restarted and put into gear it stalls. If it runs for a while..say driving 20-30 minutes it doesn't have the stalling problem.

I had it scanned for fault codes. Their were none.

I have replaced the coolant temperature sensor, the spark plugs, the Idle Air Control motor, and the fuel filter.

To review....it stalls a couple of times a week. 15 % of the time it is after it was started cold and put into gear. 85 % of the time the engine is warm...perhaps having driven 10-15 minutes and sitting at a traffic light...it stalls on its own...or it is turned off after a few minutes of driving...say to run into a store...when it is restarted and put into gear it stalls. If it runs for a while..say driving 20-30 minutes it doesn't have the stalling problem.

My WAG would be the torque converter clutch solenoid

LOL. I believe your serious. So your telling me this is how you check the basics: "when it comes to fixing a car the basics would be check battery connections then scan tool". Still laughing!

If it only stalls in gear, then I'd have to second the Torque converter lockup. there should be wiring at the brake pedal you can disconnect and then drive for a while which will prevent the lockup from happening, which if it's the cause, will prevent it from stalling.

The wife's Beretta has had this problem (TH125.) The solenoid starts to stick after a few years and doesn't unlock the torque converter when you stop, so it stalls the car out. It slowly but surely gets worse and starts to happen more and more. One way to tell is when you're driving, tap the brake - the rpms should pick up by about 200 when you hit the brake as the tq unlocks and then the rpm will drop back down when you let go of the brake as the trans locks the torque converter back up.

That said, I just solved a driveability problem on the same Beretta... EGR valve. The car set no codes and would idle like crap - like a 69 Camaro with a big cam. If you stood on the gas, it ran great. I threw plugs and wires (worn plugs and cracked wires) at it, then tried cleaning the IAC - no change. Went to the junkyard and got an IAC and an EGR while I was there. Also checked the vapor canister and the PS switch to see if it was mucking with the idle. Replaced the EGR and all done.

Also, your car is OBDII, so a good scan tool might help - not just a code reader, but a scan tool. It can show you stuff to help diagnose the actual problem, like the computer thinks it's -40 outside or something really weird and it's trying to compensate...

Ray