1997 GMC Sierra rough running & black exhaust

Tiny
GIMC2010
  • MEMBER
  • 1997 GMC SIERRA
  • V8
  • 2WD
  • AUTOMATIC
  • 146,000 MILES
Our GMC is running rough and when you accelerate quickly it spews black exhaust. Also the service engine soon light is on. The O2 sensors have been changed and if the engine gets a long use (long trip) then it goes off, but as soon as we travel around home for a little while it starts again.

Any suggestions on what can fix the problem and if it will damage the engine to continue to drive while running this way?
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Saturday, October 9th, 2010 AT 3:39 PM

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Tiny
RASMATAZ
  • MEMBER
It will you're ruining the cylinders, you gonna end up with engine compression problems

Probable causes of an engine running rich are as follows:

1. Excessive fuel pressure can be cause by restricted fuel return line or defective fuel pressure regulator.
2. Defective Oxygen Sensors.
3. Leaking injectors and fuel pressure regulator.
4. Coolant temperature sensor out of calibration.
5. Restricted air intake system.
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Saturday, October 9th, 2010 AT 5:03 PM

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