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GMC Yukon Start Stall Idle Problems

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  • Sorry it took so long to respond and I know how frustrating it is to wait for a solution and nothing. that is why I go to justanswers.com and they have certified GM techs on board to try to solve your issues. The only draw back is that if they fix your issue and you are satisfied with the answer that the Tech has given to you, then you can elect to pay them 18.00 or 24.00 or whatever. But I had to resort to this because I wasn;t getting an answer from anyone and I certainly don't want to go to the dealer and get ripped off again. This is a pretty good site for me and my Yukon issues recently and it works for DIY like me. I hope this helps you it did me.
  • Stever@EdmundsStever@Edmunds YooperlandPosts: 38,916
    Next time try Edmunds Answers. Lots of good techs volunteer their time there.

    And it's free. :)
  • aljoy1aljoy1 Posts: 2
    I have a 2001 gmc denali that runs rough in the morning - usually after it rains or sits (with humid weather). SES light blinks and code indicates all cylinders missing. Problem goes away after running 10-15 minutes (engine heats up). Dealer can't figure it out - recent wires and plugs done. Being told there is no distributor cap / rotor on this engine. Is that true? Any possibility that it is the wire harness? belt tensioners? thanks.
  • aljoy1aljoy1 Posts: 2
    I have a 2001 GMC Yukon 6.0 and the Brake / ABS lights come on and stutter stop at low speeds. Dealer says there are no codes for the wheel sensors and indicating must be the contol module - any assistance with other causes?
    Thanks.
  • We just purchased a 2007 Yukon XL with 59,000 miles a few weeks ago and it is doing the exact same thing you described. I also noticed that it will sometimes start fine using the remote start feature. I think it may have something to do with the security chip in the key.
  • gmcustsvcgmcustsvc Posts: 4,001
    Hello Lawson2212,
    I apologize that you are experiencing a concern with your vehicle. Because you just recently purchased the vehicle, have you taken the vehicle back to the dealership to have them look at it? Thank you,
    Mariah GM Customer Service
  • This just recently started happening, but while i'M driving and as i start to slow down my battery dial started to fluctuate. but as long as my foot is on tha gas it runs great. Was wondering if anyone has had this problem I had my battery, alternator, and starter tested and all results came out good.
  • I have looked everywhere on my 5.3 for an IAC, is it possible that the Evap valve does the same job, as it is located where the IAC is supposed to be? I will clean all the sensors and parts as suggested in this forum and update. Thanks! Everyone for all the Great info!
  • mag44mag44 Posts: 32
    edited October 2010
    Hi, looking for some help! 2002 Yukon Denali XL. A few months back I had some misfires so I read the codes, did some test and replace the Mass Air Flow Sensor and everything has been fine since, a couple weeks ago I drove about 3 hours and all was fine then that night, driving back I had some hesitations or misfires but it seem to go away and I made it back. Two nights ago I drove about 2 hours and all was fine. The next morning when I went to start it, It had terrible misfires (P0300),sputtered, I drove it about 100 yards and made it back to the drive and it never started again for the most part, occasionally after I let it sit, it will start, misfires and then dies again.

    It sounded like maybe a fuel pump issue but that checks out ok.

    I replaced the plugs, and wires a few months back, new EGR valve and MAF.

    There are no codes at this time.

    One more thing, I have been looking for vacuum leaks but really do not know where to start.


    Anyone have any ideas.

    Thanks in advance.
  • mag44mag44 Posts: 32
    One more thing, I have been looking for vacuum leaks but really do not know where to start.

    Thanks
  • What motor do you have? How many miles? When it "misfires" where do you hear it coming from? ie; exhaust or intake? When you crank it over does it crank slowly, normally, or quickly?...Scott
  • mag44mag44 Posts: 32
    edited October 2010
    I have the 6.0, 143K on it,it cranks normal like itt should fire. Misfire seems to be coming from intake. I am also trying to locate my Idle Air control valve but I can't not find it to test, it's not on the throttle body and I cannot see it on the intake manifold.
    Thanks for your help.
  • Do you by chance have a compression gauge? It sounds like either ignition timing, or valve timing is way out. Ignition timing would be a computer issue, however valve timing could be a more serious problem. Using a compression gauge would rule our valve timing problems.
  • mag44mag44 Posts: 32
    No I do not, I guess I may have to take this in to the shop. I'm just not sure what would throw the timing out that quick, especially since it ran fine, I parked it and then it had it's issues. Could the Idle Air control vale cause issues like that?

    I can't believe I can't find that thing to do a simple test.

    Thanks for your help. It looks like a tow to the shop!!
  • mag44mag44 Posts: 32
    Hi Fongerrlli, I have looked all over on my 2002 Denali XL and cannot find the IAC, I see nothing that looks like the replacement IAC online, silver, with a connector out the top,

    The manuals show the IAC attached to the throttle body but not in this case. There is a black cylinder about 3 " long on the left side of the throttle body with wires but that is mounted to the TB with 4 bolts, and a small black sensor on the right side which I believe is the position sensor.

    Any help would be appreciated.

    Thanks
  • Actually, There are several things that could give you the same conditions. Are you sure the motor doesn't seem to be turning over just a little faster than usual? It is common for engines to "jump time" when you turn them off. This puts the cam and crank out of synch. The timing chain connects the two and if it jumps a tooth(or more) the valves are no longer in time with the pistons,you then will lose compression and the computer will send the signal to fire at the wrong time; possibly when an intake or exhaust valves are still open. This is when you will hear the combustion in the intake or the exhaust. Hopefully this is not your problem. You can buy a cheap compression gauge for about $10 just to rule it out. There are other ways but more difficult to explain.You might want to look into purchasing a repair manual from your local auto parts store, they are pretty handy!
  • mag44mag44 Posts: 32
    Thanks, it's possible that the timiing is out, but with the prior sympton of misfires I was going down another path but who knows myabe this issue is unrelated to the previous ones. I will go pick up a gauge and test that. I have all the manuals but as usual they give a generic answer for most issues. Like where the IAC valve is.

    Again thanks for your quick responses. Call AAA to get it towed in.
  • Usually if the IAC is not right on the throttle body, it is mounted right behind it on the intake manifold. Good Luck!
  • Did you find anything out? I'm kind of curious.
  • your IAC (Idle Air Control valve) is controlled by the this and it regulates the air bypassing the throttle plate by moving the pintle in or out of the air passage . The IAC valve is controlled by the PCM The IAC is located on the throttle body and is held on with two bolts and has wires connected to it by a plug. when you take this unit out make sure the tip of the pintle to the mounting flange -press the pintle in until the distance is less than 1.1/8'sticking out.

    I don't think this part is causing your problem. It sounds like a lack of fuel or spark. but if you are misfiring it usually is a timing issue, or flat cam, or cheap gas, or timing chain slipped. let me know your findings.
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