1991 Jeep Cherokee running rich I think

1991 JEEP CHEROKEE
95,000 MILES • 6 CYL • 4WD • AUTOMATIC
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TUTTLEJ
  • MEMBER
  • 2 POSTS
my jeep blows black smoke out the exhaust, doesnt ideal very well, and also seems under powered, I pulled the plugs to check them they were alittle dirty not to bad then I started blowing black smoke so I pulled the plugs again and they were black really bad cleaned them tryed it again still black smoke and strong gas smell
Jun 22, 2010 at 7:08 AM
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RASMATAZ
  • ✓ASE Certified Mechanic
  • 75,992 POSTS
  • ASE Certified Mechanic
Probable causes of an engine running rich are as follows:

1.Fuel pressure not within specs.Can be cause by restricted fuel return line or defective fuel pressure regulator.
2.Defective Oxygen Sensors.
3.Leaking injectors.
4.Coolant temperature sensor out of calibration.
5.Restricted air intake system.
Jun 23, 2010 at 2:46 AM
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