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89 GP Stalling/Speedometer


morblee72
05-13-2004, 05:15 PM
I was wondering if I could get some suggestions on what might be my cars problem.

I have a 1989 Pontiac Grand Prix, that has a 2.8L FI engine. I bought this car for $400 back in December and all was going great with it till a month ago. The car starts up great, but the minute I let my foot off the gas, it dies, no check engine light or any warning lights of any kind. So I usually have to put it into neutral and still leave my foot on the gas & brake pedal before I put it into drive. Once the car is on the road and moving it runs just fine but the minute I have to stop or slow down to about 15mph it stalls out. At first it did it ocassionally but now it is happening almost daily. Also in this time my speedometer went screwy. It either does not work at all (most days), or sometimes it will work fine and then somedays it will start out not working but pop on as I am driving, and when not working the odometer does not keep track of the mileage, the rpm, volts, oil and fuel guages all work.

Any suggestions would be great. It has a new battery and alternator and the transmission is only 1yr old. I was told it might be the idle control valve but would like to hear some more opinions before I start spending money....Thanks for any help or suggestions.....

kilroypr
05-14-2004, 05:02 PM
Looks like a stuck converter clutch. Tell us is the same behaviour as trying to stop a manual tranny car without applying the clutch?

morblee72
05-14-2004, 07:35 PM
I forgot to mention that my car is an automatic. When I start it, I have toturn the key like 2 -3 times and I have to apply the gas and it will start, but it will stall out the minute I take my foot off the gas. I did notice if I set there for a minute with my foot on the gas I can slowly ease it off and it will stay running and I am able to to move it into reverse and stop and it does not stall. I did this on a few errands I had to make today and each time it stayed running at first, but then I had a 50 - 50 ratio of it stalling when I slowed down or came to a stop. Last night I tried this and I was shocked when it ran perfectly and the speedometer even worked but today it is back to the same old thing.

Slade901
05-14-2004, 07:47 PM
1. Take out your IAC (Idle Air Control solenoid) which is located on the throttle body. Clean it with a throttle body cleaner and a brush. Clean the spot where the IAC goes in to the throttle body.
If that does not work you may have to replace the IAC $29.

2. The TPS (Throttle Position Sensor) also causes problem which is located below the IAC. The TPS at IDLE provides voltage value to the computer and that's what how computer determine the position of the throttle plate. If there is a dead spot on the TPS providing incorrect voltage then it will throw the computer a little bit. The TPS can't be cleaned and you just have to replace it $19.

3. The MAF (Mass Air Flow sensor usually located right after the air filter box) or ACT (Air Charge Temperature sensor usually located on the side of the air filter box). Try cleaning them with some throttle body cleaner and let it dry.

Check the connectors as well of all sensors.

casinonut531
05-14-2004, 09:26 PM
I have a 88 2.8 v6

I was having that problem with my car after I replaced the tranny. I did a read out on it and it was my MAF - mass airflow sensor. It ran me 95 dollars plus exchange, but it fixed the problem. If you engine is like mine, which I think it is, your MAF is connected to your air housing. If you car came equipped to do a digital read out yourself you should do one. If you dont know how let me know and I will walk you through it. Hope that helps

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