Hesitates

1999 GMC SIERRA
190,000 MILES • V8 • 4WD • AUTOMATIC
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MJC454
  • MEMBER
  • 1 POST
I have a 1999 gmc ext. cab siera w/5.3 L , w/ 190,000ml and it runs good it dont miss fire or run rought , But when i turn the air or heat on it starts to run rough almost like its miss-firing and when i take off from a stand still it hesitates and when i turn it off it goes away and plugs are under a year old.
Jul 16, 2011 at 3:35 PM
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RASMATAZ
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 75,992 POSTS
Hesitation:

Could be one of the following below -check and test:

Oxygen sensors.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position 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.

Note:If it doesn't apply disregard.
Aug 11, 2011 at 10:41 AM
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