I have a 2000 chevy blazer 4x4 4.3 liter with California emmisions. I am having a problem with a tip in hesitation. That is as soon as you step on the pedal to accelerate the engine hesitates or misfires and then clears up. It seems to happen only when the engine is cold and once its warms up to operating temp it is gone. The truck also seems to be hesitating at highway speeds around 60-65mph. Scan data shows that long term fuel trim is 10% + so I think the PCM is trying to compensate for a lean condition. Recent work performed include new fuel pump and full tune-up all using factory gm parts. Can a small vac leak cause this problem. Has anyone ran into this before? Any ideas to repair? Thanks!
- posted
16 years ago