Mechanics

ENGINE IS HESITATING UNLESS I ACCELERATE HARD

1999 GMC Sierra • 150,000 miles

I have 1999 gmc sierra 4x4 5.3v8 regular cab When I am driving at 40-50miles an hour and have to slow down to say 30 and then speed back up it hesitates and jumps unless I mash the gas then it moves i've replaced spark plugs, air filter, fuel filter and transmisssion filter
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Terpfan
October 25, 2011.




Could be caused by one of the following below

Oxygen sensor.

Catalytic converter.

Fuel injectors dirty/sticking.

Mass airflow sensor/Airflow meter.

Throttle position sensor.

Crankshaft position sensor

Knock sensor

Manifold absolute pressure sensor.

EGR Valve

Fuel pressure regulator leaking or defective fuel pump.

Fuel contamination.

Foul/defective spark plugs.

Open spark plug wires.

Ignition coil/Coil packs defective.

Incorrect ignition timing.

Cap and rotor.

Tiny
Rasmataz
Oct 26, 2011.


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