Engine Performance problem
1998 GMC Jimmy 6 cyl Four Wheel Drive Automatic 135000 miles
After 30 minutes of highway driving my motor starts to cut out, the max RPM that this happens at will steadily drop. If I pull over and shut the motor off it will run better for a few minutes before it starts happening again. Warmer outside temperatures seem to make the problem worst. I have found that if I ease into the throttle the RPM's will climb again but if I step on it the motor falls on it's face.
Here is a list of what I have tried so far:
throttle positioning sensor
mass air flow sensor
ignition control module
I have also looked for vacuum leaks, I found none.
have the same problem?
Wednesday, March 24th, 2010 AT 7:29 PM