99 c1500 5.7 suburban missing at idle when hot

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by i_build, Oct 10, 2009.

  1. i_build

    i_build Rockstar

    145k miles. Miss in gear at idle after hot... more when a/c is on. Idles at about 600 RPM is that too low?

    When it does this after I accelerate off idle it clears up. Fuel pressure is good. Drove over 600 miles today at 90mph super smooth... Other than the idle issue... she runs great.

    New plugs, cap and rotor, plugs, fuel pump, and fuel and air filter about 5 months ago. Wires not replaced yet (could this be the culprit?). Nothing changed recently that may have triggered the problem.

    Also forgot to mention new fuel press reg 3 months ago.


    After a bit more reading I see this is not an easy one to ask... saw something about the gears on the dizzy wearing... and something about the poppets... when i was in there changing the FPR I should have cleaned them.... ooo well the debugging goes on.....
    Last edited: Oct 11, 2009
  2. i_build

    i_build Rockstar

    More info... Had to drive back 300 miles and half way through the trip couldnt make it up hill. Pulled over for 5 mins with the engine off and I was able to drive another 30 miles before it happened again. Stopped again for 5 minutes and then drove again for about 30 miles. Did that all the way home.
  3. nedder

    nedder New Member


    Were you able to determine what the issue was and were you able to fix it?
  4. i_build

    i_build Rockstar

    Not yet. Get my paycheck tomorow so a set of wires is in the budget (need them regardless of whether they are the problem), and a test for the cats along with a vac leak test.

    I think the symptom is to vague for a direct solution via threads.

    Got a new clue though... every once and a while in the past I would turn the key to start the truck and just get a click second time I turned the key she would start. That happened maybe once a month... Since I got back from my long drive she has been doing that every day... Makes me think that the bat or the bat cables may need to be replaced as well.

    If I find the issue I will post back.

    If anyone has a good debug game plan for these symptoms please chime in.


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