1992 Chevy Truck Igntiion/Fuel Question

1992 CHEVROLET TRUCK
95,000 MILES • V8 • 2WD • AUTOMATIC
Avatar
THOMAS KIRKPATRICK
  • MEMBER
  • 1 POST
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
Feb 15, 2009 at 3:43 PM
Advertisement
Avatar
RASMATAZ
  • CERTIFIED EXPERT
  • 75,992 POSTS
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
Feb 15, 2009 at 3:55 PM