Question my grand am does fine in the morning then after about 4 hours on my mail route ,it stalls as if it is running hot. the temp never reaches above 200 . if i let the car cool down it will run fine again. i have replaced the crank sensor o2 sensor radiator, filters and have tuned it up ,the car has high miles but it still drives great when its cool
AnswerHi
I would suspect either the fuel pump, or the Coil Housing.
If possible, I would have your mechanic attach a fuel pressure gauge to the vehicle and drive it until it starts to stall. You should see a significant decrease in fuel pressure as it gets close to stalling.
(eg from 42psi to 20 or lower).
Have them inspect the Fuel Pressure Regulator, check the Vacuum source line for evidence of fuel. If any is found, that MAY be your problem, although unlikely.
If the pressure stays good, I would then turn my attention to the Ignition system, specifically the Coil Housing and or the coils themselves. Also check the ICM (Ignition Control Module).
Also have them scan the PCM for codes, just to make sure all the other related sensors are functioning properly.
After that check the Cat Converter.
All are JUST advice from experience.
I Hope this helps.
Good Luck
Pawl
