1996 GMC Suburban skipping

1996 GMC SUBURBAN
125,000 MILES • V8 • 4WD • AUTOMATIC
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JIMILY
  • MEMBER
  • 1 POST
I've got a 95 Sub with 7.4L 454 engine. When idling, it has uneven firing, and when accelerating from a dead stop, it stumbles. I have no engine lights or other indications of codes. Any ideas?
Feb 8, 2010 at 6:04 PM
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RASMATAZ
  • ✓ASE Certified Mechanic
  • 75,992 POSTS
  • ASE Certified Mechanic
Inspect and test all the following listed below:

Oxygen sensor
Catalytic converter
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)
Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Cap and rotor

Note:If it doesn't apply disregard.
Feb 8, 2010 at 9:32 PM
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