2000 GTP stalls on Expressway

I have taken car to 3 different pontiac dealers. 1st dealer cleaned fuel injectors and put in new fuel filter. Car still continued to stall on highways, stops and in traffic. 2nd and 3rd dealer couldnt find anything wrong with it after doing some diagnostic testing. Asked if the sensors could be bad, and they said the readouts on the ohmeter are all fine. There are no error codes in the computer. Ready to give up and trade it in. Can anyone help? Oh, I also had the fuel pump resistor changed about 1 year ago after it stalled on highway and wqouldnt start.
I appreciate any insight you guys can give me.

It sounds as if you are having a problem with the CPS/Crank Position Sensor....I take it, you must have a 97/03 Grand Prix and that will cause that kind of problem and wount throw a code.Most dealers have a problem detecting that :disappoin .It is located behind the harmonic dampner.Here is a pic of the part and the parts cost is about 30 bucks on-line or around 45/50 bucks thru the dealer

You must pull the passenger wheel, fender lining, both belts. Get a big impact wrench 400-500 ft-lbs and spin off the crank bolt. Get a harmonic balancer puller and pull the crank pulley/balancer assembly. The CPS is a plastic piece with a weatherpack connector going to it located just behind the pulleys. there a plastic shield around it that must be pulled as well. Takes about 2 hours




http://www.rockauto.com/ref/ACDelco/213-151.jpg

When CPS was shot on my 97 GTP, I had SES light, and dealer could read code.

Thanks for the reply. I mentioned the CPS to the dealer and he couldnt find anything wrong with it. He said he didnt want to change anything unless absolutely sure. Ill take it to a buddy of mine and see what happens and fill you guys in.

Have your buddy check the harmonic balancer for cracks as well, as this will cause CPS like symptoms due to the balancer wobbling

Couple days ago, I had bad fuel pump connector, replaced a new one. Try to see if this helps.

Changed the Crank positions sensor 3 days ago and the car hasnt stalled since. Thanks BIG-L. looks like that was the problem.