What should I do about these codes

Discussion in 'General Chevy & GM Tech Questions' started by hkinsland, Mar 15, 2009.

  1. hkinsland

    hkinsland New Member

    I just bought a 2005 GMC Sierra 1500 with the 5.3 liter and 31k miles. Yesterday I hauled my camper about 60 miles to the dealership that I bought it at for some service work. While I was accelerating up a hill, the check engine light came on and flashed 6 or so times. I let off the gas and it went off.

    When I finished dropping the camper off, I was pulling back out onto the road and the engine stumbled and the light came back on steady. From there on out, when I pulled up to a red light and stopped, it would almost die. It did fine on the highway though so I went on home. I went by Autozone and they scanned it pulling the P0131 and P0171 codes indicating a lean reading on Bank 1, Sensor 1. I don't want to overreact and change out the o2 sensor as it may not be that so any feedback from you guys would be great.

    We also have a 2004 Tahoe with the 5.3 liter and I have noticed that my Sierra does not seem to have as much power as the Tahoe but I assumed that had more to do with the 3.73 rearend in the Tahoe and the 3.42 in the Sierra. Don't know if this would indicate anything.

    Thanks for the help!
  2. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    When ever you have an O2 code the very last thing you want to do is change the sensor. Something upstream is usually causing the problem. Vacuum leak, dirty injector or Airflow sensor. Reading the fuel trim on a scanner will really help pinpoint the problem.
  3. daddytech

    daddytech Epic Member 5+ Years 500 Posts

    I'd run some Sea Foam through it first and drive it around a bit before considering changing out the O2 sensors. My wifes suburban was giving codes for the O2 sensor right after Christmas, ran sea foam through it, had her use a couple tanks of super (since the price was down again) and the light hasn' t come on again for that code again since.

    try that before anything else and see what happens,, you are talking $7.00 versus around $80.00+ each for the O2 sensors

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