2017 Denali fluttering when accelerating. VIDEO

Discussion in 'Engine & Drivetrain' started by denali17gmc, Mar 16, 2017.

  1. denali17gmc

    denali17gmc TYF Newbie

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    Picked up a 2017 Denali just over a month ago, been hearing a "fluttering"/rattling type sound when accelerating. I'd say it usually happens at about 1500-1700 RPM... occurs when you're asking for a little more speed and usually stops when at cruising speed.

    Dealer said it's the sound of some exhaust valve with the purpose of keeping the muffler quiet... is this normal? Seems too loud to be normal. Video attached.
     
  2. thavngr98

    thavngr98 TYF Newbie

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    I have the same problem on my XL. I think its an exhaust leak. Going to the dealer next week. See what happens
     
  3. denali17gmc

    denali17gmc TYF Newbie

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    That's what I was told when I took it in for service. They changed the entire exhaust and the issue still persist...
     
  4. denali17gmc

    denali17gmc TYF Newbie

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    Please keep me posted on what they say.
     
  5. thavngr98

    thavngr98 TYF Newbie

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    will do!
     
  6. MikeW

    MikeW TYF Newbie

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    I am having similar issue - but its on a 2002 with 278K.. thought it might be transmission going.... please keep us informed!
     
  7. Fred Bickley

    Fred Bickley TYF Newbie

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    Can't really tell from your video, but if it is a shudder, it could be the torque converter. I just had my 2016 Denali in and they replaced it fixing the issue. I had a shudder at the gear changes that happened between 1200 to 1900 RPMs on gears 3 through 6. There is also a software update that might be necessary as well.
     
  8. jeffbco

    jeffbco Full Access Member

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  9. Tacky

    Tacky Member

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    I believe you are hearing characteristic noise that comes in with V4 engine operation. The valve in the exhaust is intended to minimize it. I don't believe there is anything that will eliminate it in the long term. I have seen several exhaust systems replaced for this but the noise comes back.
     
    Naz 16 SLT likes this.
  10. Nashoba

    Nashoba Member

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    I assume you have cylinder displacement down to V4 and you know about the flapper valve that a lot of folks complain about. We have V8 to V4 on our 2008 Tahoe Hybrid and my wife was complaining of the same stumbling the other day. So, I did an Oklahoma quick tune up on the vehicle. I got it up to operating temp and then performed several 60 to 90 mph runs in quick succession. Then I let everything sorta cool down to normal, although the temp gauge never moved up, and them performed several 20 to 98 mph (darn engine electronic governor) runs to continue the "tune up". When I got back to town and drove through town so I would have to stop at lights and stop sighs, I noticed no stumbling or hesitation at all. I was even able to climb a steep hill on electric motor only on the way to the house. That is the first time I'd been able to ever do that. The Tahoe is my wife's vehicle and she is a very "gentle" driver and hardly ever hits passing gear so it can get clogged up. I also put a half can of Berryman's B12 Chemtool in the gas tank which was about a quarter full before the "tune up". After I got through, I put a full can in the tank and filled it up with no ethanol fuel regular. I will add another can and a half of Berryman's to the tank the next fill up. A can treats 20 gallons of fuel. Sometimes you just gotta blow the soot out of them. But you have to find a safe stretch of road to do it!
     

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