Question about 1999 GMC Sierra

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99 gmc no power when passing or climbing

99 gmc 4x4, truck is mechanicly taken care of, problem is if i trump on the gas the truck will hesitate, motor sounds muffled, pinging noise like bad gas, shifting is held back. If I ease into to it, to go faster, it works fine. Great accelleration, smooth, shifts nice. I have changed: plugs, wires, TPS, MAP, MASS, intake gasket, fuel filter, air filter, had the injectors cleaned and tested, fuel pressure is good, changed all O2 sensors. What could this be????

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  • Anonymous Mar 19, 2014

    Smell raw gas, fuel gauge stuck on full, hesitates


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It could be electric fuel pump stall. The pump isn't pumping fuel fast enough. This model may have a inline fuel filter before the fuel pump as well that might need replacing.

Posted on Dec 02, 2008

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Have the same problem replaced both pumps and the fuel filters tune up and oil change still does the same thing think its the fuel pressure regulator now!

Posted on Dec 16, 2009

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