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GMC Yukon Start Stall Idle Problems



  • I have a 04 denali XL with a little over 76,000 miles and surprisingly this is the first problem I ever had with it. Last week, my wife was driving it and came home. I got in it and went to pick my kid up from the bus stop and was on a decline and little did I know, it was low on gas. When I restarted the vehicle, it sounded as though it was flooded. but after 3 tries, it started and I took it home. After getting home, I started and shut it off, repeating the process several times to see if it was just me or the truck. After letting it sit overnight, I woke the next morning and tried to start it and it again sounded like it was flooded. But it always starts on the third try. I haven't taken it to the dealership and really don't want to because I know that if I do, the police might have to drag me outta there with the BS that they try to give out so any suggestions would be great. Thanks in advance. :sick:
  • Were you assuming that it sounded like it was flooded? When you say flooded, did you smell gas? or did the engine just kept cranking over and over and no hope of catching a spark? You might want to check the gas filter? since you were on a decline and on very low gas (this is where all of the junk from the inside of the gas tank and fuel goes through the system and gets the fuel filter plugged with crap). Secondly, if that doesn't work check your mass air control unit. But since this is a newer vehicle, if you can borrow the tool that plugs into the computer of the car it will indicate to you (by code) what the issue is with your Denali. I hope this helps and let me know the status...
  • 2004 Yukon Denali XL, engine 6.0L, all wheel drive. On around 09/01/09 my parents started to feel that their vehicle was stumbling, hesitating, or stalling on at acceleration. This vehicle would start and idle with no problems, but at hard acceleration the vehicle would hesitate really bad and generate a code P0336. I searched the code and it was for P0336 “Crankshaft Position Sensor A Circuit Range/Performance”. Bought a new crankshaft position sensor from an autoparts and installed it. With the new sensor the vehicle would just crank and not start. Soon it would generate a code and it was P0335 “Crankshaft Position Sensor A Circuit Malfunction”. Removed the crankshaft position sensor and returned it to the autoparts, they gave me another one to install. It also did the same and generated the P0335 code. Removed it and returned it to the autoparts and they gave me another one which it also gave me the P0335 code. After the third crankshaft position sensor, the autoparts gave me my money back. I went to the dealer and got me a new one, which are made from ACDelco for $87.03. Installed it, the vehicle started right away, took it for a test drive and all the stumbling, hesitation, and stalling were gone.
    Note: The crankshaft position sensor is located in the passenger side of the vehicle. It is between the starter and motor.
  • I guess I was assuming that it was flooded but did not smell gas. She still cranks on the 3rd try and I hear my fuel pump kick in everythime I turn the key. I had her on the highway yesterday at high speeds and everytime I punched it, she took off with the power that she always had. She never stalls or shuts off and I see that she is gettting fuel, but on the way back, my service light came on and I took it by the parts store to read the codes, and they said that the connector wasn't getting power so they couldn't read the codes. But this morning I went to the store and it was on when I got there. Switched the truck off and went inside and came out 5 minutes later and did the 3 try start thingy and the light was off. I'm thinking that it may be a computer problem or something as well. I did just recently get a new battery installed. Wondering if you have to reset the computer when installing a new battery? But I will also replace that crankshaft position sensor and see what happens. Thanks for the responses as well everyone.
  • just got back from dealer,again.brought all my info on the recall and told him that i read about others having same problem.he told me,again,that the trucks computer needs to pick up the problem so they can fix it,and that he can't remember a recall.this is what we are dealing with.he stated that they reprogrammed something to do with the sluggishness the car was having.again,nothing found that would address the problem of my truck stalling.and i can't turn the truck in like i posted is a new program and you may return the vehicle if not satisfied if you purchased it between sept.15 and oct.15.i purchased my truck in late calling gm today,i will post what they said.
  • Hello to all, I have a 2002 Denali, which had the engine (a used 6.0) replaced after the original took in water. The replaced engine is also a 6.0 but a 2005 and not a 2002. Since the replacement of the engine, the Denali's service engine light has been on, and runs rough (with the service engine light blinking) after you have gave it gas and the vehicle has been at high rpms to pass a vehicle. Recently, the fuel pump and crank sensore were replaced and the codes were cleared, which I thought had corrected the problem. The vehicle ran great with no service engine light for about three days and then suddenly started the same nonsense. Can anyone help? Thanks in advance.
  • My Denali just started idling funny. When sitting at an idle, it will every once in awhile act like its going to die then go back to idle again. It also does this when driving it when I come to a stop. I tried it out last night and every time while sitting in park I give it gas then let off it acts like its going to die then goes back to idle again. Any ideas?
  • Sounds like you have a dirty IAC (Idle Air Control Valve) which is the silver unit just before the throttle body on the top of front of engine. that could possibly be dirty or dirty fuel lines, dirty injectors. What is the idle at when it is normal, i.e. around 600 rpm or lower? And when you say its getting ready to die, look at the idle needle on the tachometer and if it falls below 400 or under it will die. If you know anyone that has a scanner or a diagnostic tool, it will tell you the code and I can look it up for you. Also, in the old days before fuel injection, we use to have carburetor with air fuel mixture screws and idle screw so that we can adjust the idle to where we want it, but in yours the IAC controls the idle and the PCM ( Powertrain Control Module) controls the IAC. Let me know what happens.
  • Our Yukon will crank but not start Ive replace the fuel pump and fuel psi reg and still the same thing help
  • So I have replaced the air filter, spark plugs, and fuel filter. I also had the alternator and battery checked for s&g's. Still have the same problem. The vehicle idles around 500 rpm or a little lower. I have not been able to locate the IAC. I have added some of that fuel injector cleaner additive to my tank to see if that helps. When it acts like its going to die it hits about 300 rpm according to my tachometer. I will check that next. It is supposedly on the air intake next to the alternator. Any other ideas if the IAC doesn't pan out.
  • I cleaned both the mass air sensor and the throttle body. It appears to have addressed the problems I was having. There are spray cleaners for both of these items. Just be careful and follow the instructions on the cans.
  • The IAC is attached on the front before throttle body unit EFI (electric fuel injection) its small aluminum color and has plug to it and it is at the end of the plastic air intake unit where the hose clamp is located. Be careful in handling this unit and spray a special cleaning spray (get from auto parts store) the IAC and re-install it and see if the idle goes back up to 600 rpm. when cold the idles should be around 1,000 or so and after it warms up in gear around 550-650 rpm. If you have the heater or a/c on it affects the idle too so make sure they are turned off. Do some research on the IAC (Google it) or go to u tube and type in "how to clean my IAC unit properly"
    I hope this helps.....
  • mamommamom Posts: 2
    I own a 2007 Yukon with approx 40K miles. Twice in the past three months the check engine light has flashed on for about two seconds and when that happened the engine derated and then all is fine. The other day on a trip the engine light flashed on and did the same thing. About 20 minutes later it did it again but this time the messages that flashed are stabilitrack disabled, engine power reduced and then the car shut down on the highway going 70+ miles and hour. The car then would not start. My husband wiggled some wires and the car started. We got to our destination and then home no problem. We took it to a mechanic to check the codes before bringing it to the dealer. NO codes showed up on the computer. Any thoughts on what this could be? I drive this car with my children all the time and do not feel safe.
  • rshtrsht Posts: 277
    Per you description, it does sound like some sort of bad connection. Can you describe what wires did your husband wiggled and if the wires lead to the engine in-take area?
  • mamommamom Posts: 2
    Not sure on exact wires but I believe they did go to the engine intake area. he also changed the relay??? Had our mechanic look it over and he said all wires looked ok-nothing obvious and b/c no codes were detected there's really nowhere to start. Spoke to the GM dealer local to us and basically said the same thing and wait til it happens again-not very comforting. Seems odd that a vehicle can completely shut down and the computer doesn't pick up any codes.
  • Important. If you have to replace a your 02' IACV, GMC will make you buy the WHOLE Throttle Body Assembly @ a cost of $850 bucks. They will not sell you the IACV individually, and you can not buy it new from any WEB SIGHT parts house. The ones they claim FIT, ARE THE WRONG APPLICATION!

  • Clean throttle Body!!!! U may need to replace the Throttle position sensor or Idle air ( manually clean it out. 80% of your problems will begin in the Throttle Body!!

    FYI............GMC will not sell U a Idle Air. They make you by the Whole $850 TB assembly. Dont attempt to buy from Online auto parts house! They will not fit!!!!
    Model's referenced 2000-2002.
  • mrkuhlsmrkuhls Posts: 3
  • so how many miles do you have on the suv? did you check the brake fluid level? Or it could be a loose wire to the computer? I need more information that this?
  • mrkuhlsmrkuhls Posts: 3
  • mrkuhlsmrkuhls Posts: 3
  • kehlkehl Posts: 3
    been havin problems with our yukon starting. so we had it narrowed down to the ignition switch, brought it to the dealer and had it replaced. it ran great for a little over a month. then it started losing power when we were driving. i would press the gas pedal then nothing. the car died on the side of the road, we sat for a few minutes then crawled home. next day started fine then it started acting up again. i was pretty sure it was the mass air sensor so i bought one from the junk yard put it in the car ran great. turned the car off after my test drive now its doing the same thing it did before the ignition switch was replaced. there is a clicking noise in dash when i turn the key but it wont turnover the ignition lights dont turn on either. starter will spin if jumped but the car will not turn over. any suggestions im at a loss
  • Sounds like the fuel pump is gone my friend. Had the same issue with my 04 Denali XL and it was losing power on the highway. Replaced it myself and it now runs like a champ. Also if you see that your gas gauge and miles to empty are changing from how they used to be...its definitely the fuel pump. Mine did the same and once I changed still wasn't showing the right miles to empty but on the second fill up it went back to normal. A month later and she's still running like a champ.
  • kehlkehl Posts: 3
    but would the fuel pump cause the car to not ever turn over. the only sound i hear is a faint click in the dash
  • gmcustsvcgmcustsvc Posts: 4,251
    I am from GM Customer Service. I would recommend at least taking it to the dealership and have the vehicle diagnosed. That way you’re not guessing what the problem is, and you can figure out how to proceed from there. Thank you.
    Mariah GM Customer Service
  • kehlkehl Posts: 3
    hey mariah
    thanks for the advice but we did take it to the dealer when the ignition switch was replaced and they couldn't find any codes or anything else wrong. they told us the only thing they could think of was the ignition switch. 500.00 and one month later here we are again. we got the car to start this morning with an ignition fuse, but as soon as the car warmed up the acceleration problem started again. we called our dealer everyone is scratching they're heads. so if anyone out there has any clues we would be happy to be enlightened. so far we have replaced the starter relay, the neutral safety switch, the ignition switch and the mass air sensor
  • ed_derieued_derieu Posts: 1
    Cleaning the IAC worked for me. FYI it was not that dirty so clean it anyway.

  • benculvbenculv Posts: 2
    About a week ago my Yukon started to have a starting issue. It will not always start on the first try but always starts on the second. There are a few things that I found while trying to diagnose this problem. It dosen't matter if the engine is hot or cold and it only happens about 50% of the time. If I turn the key to the on position and wait about 3 seconds and then turn it to the start position it starts every time. One other thing I found was if I try and start it on the first try it cranks but does not start and then I release the key to the on position it continues to crank for about 2 to 3 seconds. I then turn it to start and it starts right up. At first I thought it was fuel pressure problem but seeing that it continues to crank after releasing the key from start to on I was thinking it may be an electrical issue with the ignition. If it does start and I release the key to the on position it never continues to crank. It runs fine after it's started. I appreciate any help in where I should look or what to try next. I am leaving on a fishing vacation next week and I will be towing my boat and I would like to try and fix this before I go.
  • Did you ever get a response to this starting issue? Im having the EXACT problem with my 06 Avalanche... Chevy says bring it in and if its the ignition cylinder Im looking at 600 bucks.
  • benculvbenculv Posts: 2
    No response from anyone on my issue from this site. I did talk to someone else about this and they told me to try changing the fuel pump relay. They said it was the easiest thing to start with. I am going to get one tonight and try it.
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