Mechanics

CHEVY IGNTIION/FUEL QUESTION

1992 Chevrolet Truck

Engine Performance problem
1992 Chevy Truck V8 Two Wheel Drive Automatic 95000 miles

The gas mileage dropped on my truck from 19 to 14. I have changed the O2, Temp Sensor, and the Knock Sensor. I seem to feel the timing being pulled back when running at 70 with the cruise on. Otherwise the truck runs fine. Could this be the ignition module? Thanks
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Thomas Kirkpatrick
February 15, 2009.




Could be one of the following below

Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include: Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires

Tiny
Rasmataz
Feb 15, 2009.


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