99 tahoe looses power pulling heavy loads uphills

Discussion in 'General Chevy & GM Tech Questions' started by paradise1, Dec 31, 2010.

  1. paradise1

    paradise1 New Member

    When I pull my utility trailer with a heavy load up steep hills the truck continues to lose power unless you keep your foot in it. It ends up shifting all the way to low. After I reach the top of the hill it has no power. I turn it off and something resets under the hood, it sounds like a door opens or closes, then it runs perfect until the next hill. I took it to a dealer in Casper WY and the replaced the fuel pump. This did not fix the problem ($784 later). It runs fine most of the time, but sometimes when I turn it off and restart it soon after shutting it off it hesitates for a while even without a heavy load. They said it had several codes like the MAP sensor, Cat back pressure but they all clear after you turn it off and then restart.
  2. stephan

    stephan Rockstar 4 Years 5000 Posts

    I'm not familiar with the sound you describe as a door opening, but this sure sounds like a fuel delivery problem. The fuel pump was a good shot because so many of them fail, but has anybody checked the fuel pressure regulator? Also if you can borrow a fp guage, hook it up & drive a steep hill with a load & see what the pressure does. It may be dropping like a rock.
    Plugged cats & exhausts can also cause lack of power & it's cumulative at higher speeds.
  3. retired2001

    retired2001 Epic Member 5+ Years 5000 Posts

    Welcome to the G M T C ! I thing that Stephen is "right on" on your power problem and I'd bet on the cats.
  4. paradise1

    paradise1 New Member

    the dealer in Casper WY checked the whole exhaust system and said ther was no problems
  5. Enkeiavalanche

    Enkeiavalanche Loving the Outdoors Staff Member 5+ Years ROTM Winner 5000 Posts

    What gears are in the truck? Did you change out the Gas Filter? Air Filter?
  6. paradise1

    paradise1 New Member

    The dealer replaced the fuel filter and it has a clean K&N air filter

    ---------- Post added at 01:53 PM ---------- Previous post was at 01:51 PM ----------

    The gears are whatevey came stock

    ---------- Post added at 01:54 PM ---------- Previous post was at 01:53 PM ----------

    what ever came stock
  7. stephan

    stephan Rockstar 4 Years 5000 Posts

    How did the dealer check the cats? What did they do?
  8. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    There is no sensor/code for Cat back pressure.

    Dump the K&N, go back to a paper filter. That is causing your MAF issue. Hopefully you can just clean the MAF rather than have to replace it.
  9. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    *****thread moved here********
  10. Looey

    Looey Rockstar

    EGR valve. Have it checked.

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