Engine Performance problem
1998 Other GMC Models V8 Two Wheel Drive Automatic 183000 miles
Greetings, I recently started experiencing very poor acceleration at wide open throttle, and/or near wide open throttle, for instance when accelerating on the on-ramp of a highway. Moderate acceleration is fine though and at an idle, the engine is silky smooth. I've already eliminated many possibilities, but I'm presently suspicious of fuel pressure. The specs for this vehicle are supposed to be 55-60psi, and 66 at WOT. I put a guage on it and see that at idle it's about 55, mild to moderate acceleration it's about 58, but it drops to about 52 at WOT. My question is this. Is 52psi at WOT low enough to possibly be causing my problem? I replaced the pump about 2 years ago but never measured the pressure before this. Also, can the ECM control fuel pressure (measured at the test port)? Could the pump be good, yet the ECM is preventing it from supplying the specificied 66psi at WOT? Thanks in advance. --Mike
have the same problem?
Sunday, August 3rd, 2008 AT 5:02 PM