Loss of power, will not go over twenty mph

2003 GMC ENVOY
185,000 MILES • 4.2L • 6 CYL • 4WD • AUTOMATIC
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ELIZABETH NICOLE RAY-LUPARDUS
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This is the SLE model. It will not go over twenty mph, has loss of power. We have replaced fan clutch, serpentine belt, throttle body with TPS, and an oil change. We are at a loss as to what it could be.
Nov 3, 2017 at 9:42 AM
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STEVE W.
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Check engine light on? Loss of power could be many things, from a plugged exhaust system to a bad fuel pump, from a failing transmission to a bad PCM.
You need to put a good scan tool on it and see what the computer is seeing and what it is doing as the engine runs.
Nov 3, 2017 at 11:06 AM