'93 Bonneville stalling issues

[scooter72908]

I’m the original owner of a ’93 3.8 L bonneville with 117,000 mile I started having stalling, dying and acceleration problems when the car is at the operating temp of 200°. When I’m slowing down and coming to a stop it will die. If I floor the gas pedal the car hesitates and will just sputters. The cold operation appears to be normal. I have viewed other threads and have checked the following to no avail. I changed the fuel filter, checked the spark plugs and gap, and checked plug wires. I checked and replaced some vacuum line hoses. I removed the air duct, the IAC, and the Mass Flow sensor from the Throttle Body and cleaned throttle body with throttle body cleaner. The IAC had some carbon build up and the throttle body was dirty. I checked the TPS voltage I had .4 volts when closed and 5 volts when throttle fully open. This voltage was taken at the ECM. I checked the injector resistance 12 to 13 ohms. I listened to each injector each one ticking.
I checked fuel pressure, which is 35 psi. and there are no codes on the computer. I am at a loss and would like some feed back.

[GTP Dad]

Check the Crank Position Sensor. It is probably going bad and not sending a proper signal to the computer. The only other thing is to check the EGR valve which could be blocked and causing you problems. They only work when the engine is up to operating temperatures. If the passage gets blocked the car will run badly. They are not hard to clean and most generally will not send a signal to the computer and give an error code until they stop operating entirely.

[DMP43]

I encountered a similar problem on my 94. Same symptoms. Check the Throttle Position Sensor mounted under the throttle body. Test by disconnecting the electrical connector and going for a short ride. If there is no difference in performance then the TPS is likely a goner.

Apparently this is a common failure and doesn't always show on the diagnostics. It is a b&%ch to get at and the Phillips screw may strip. Also do it when the engine is cold. When I installed a new one it was a new car! Great acceleration, tranny kickdown, and NO STALLING!! $90 Canadian at the part store (Canadian Tire). Give it a burst!

[scooter72908]

I removed the EGR valve and cleaned, there was very little carbon build up. I cleaned and reinstalled. I will look at the Crank Position Sensor today. GPT Dad, is the a way to check the sensor without removing it or a test that I can do to verify that it is working. I never removed this part before, any pointers. thanks,

[scooter72908]

Well I drove it this morning before checking the crank sensor and it died while stopping, and the engine was still cold. Any ideas?

[GTP Dad]

Generally no there isn't any way to check it. When the car stalled did you get a check engine light? If the CPS went out totally then it should have thrown you a code. Also some of the 3.8's have two CPS' so make sure you check both. You may also want to check and clean the Mass air flow sensor. It can cause a car to stall.

[scooter72908]

Well it's fixed!!!! but not be me.
I had taken it in too the local Pontiac Service dept. yesterday, after it died six times trying to make it to work. After their diagnoses they said that my fuel pump was not putting out the pressure it should. Which should be between 41 and 47 psi. Since my problem was getting worse and I and my family was tired of me working on it in the evenings I told them to fix it, and for $517.00 they did.

Side note...I think my fuel pump was okay, because they showed me the the screen sock that was inside the tank and it had completely flattened out(colapsed)and you couldn't see light through it.

I would like to thank everybody for there threads and for this awesome fourm, and I also hope that this information I provided will also save sombody some time and money.