1996 GMC Safari code P1133

Tiny
CML5456
  • MEMBER
  • 1996 GMC SAFARI
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 146,787 MILES
Had this GMC(4.3 L) van been sitting for a while, recently started it up for a smog test, but check engine light stays on, pull the code says p1133 manuf air fuel ratio mixture. So I replaced the pre-cat O2 sensor, reset the code, but check engine light came on again after about 20 miles of driving, should I replace the other O2 sensor togeter with the first one? I wonder what the real problem to this check engine thing. Thanks for any professional mechanic advises.
Wednesday, May 6th, 2009 AT 10:22 PM

1 Reply

Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Does it have 2 sensors befoe the cat? The code is for the drivers side bank of the engine. Does the engine miss? Check for vacuum leaks, tune up, exhaust leaks. If all ok, the sensor may be bad, but a scan tool is needed to watch the MAP and o2 sensors to see what is going on. It could be bad injector, vacuum, misfire, many different things, even just a bad o2 sensor on that side of the engine
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Thursday, May 7th, 2009 AT 8:20 AM

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