Loud humming while accelerating

[James M12]

Hello

 

I just purchased a 2016 Suburban LTZ and noticed when I am driving and slightly press on the gas petal I hear a very low frequency humming sound, almost like a deep bass sound. You can feel it in the gas petal as I take my foot on and off the pedal. If I apply more pressure and accelerate, the hum goes away or if I take my foot off the pedal. Seems to be only when have very little pressure on the gas petal, maintaining my speed.

 

I saw the PIT5404B, and not sure if this is related or not, not sure what 'buffeting' is. But it's really annoying and just got the car, so I'm not sure what my options are.

 

I've seen other gmc threads about exhaust or front differential etc, but wanted to see if other have the issue or can point me in the right direction.

 

Thanks for any help.

 

James

[The Zip]

5 hours ago, James M12 said:

You can feel it in the gas petal as I take my foot on and off the pedal. If I apply more pressure and accelerate, the hum goes away or if I take my foot off the pedal. Seems to be only when have very little pressure on the gas petal, maintaining my speed.

There is a lot of owner information on this forum about your 2016 SUV on buffeting, pressure, shaking, and vibration.  No solid fix from the manufacturer.  As the years increased 2017 thru 2019, manufacturer trial and error could have minimized the impact of some of the effects.  You should read a few pages to compare with what you are hearing.  Slight chance something else is going on, but the way you describe it sounds like AFM is kicking in under slight pedal with 4 cylinders struggling to move the weight of your truck.  When you get off the pedal to coast or give the truck more pedal to kick in all eight cylinders makes sense that you would not hear a hum.

[James M12]

 

1 minute ago, The Zip said:

There is a lot of owner information on this forum about your 2016 SUV on buffeting, pressure, shaking, and vibration.  No solid fix from the manufacturer.  As the years increased 2017 thru 2019, manufacturer trial and error could have minimized the impact of some of the effects.  You should read a few pages to compare with what you are hearing.  Slight chance something else is going on, but the way you describe it sounds like AFM is kicking in under slight pedal with 4 cylinders struggling to move the weight of your truck.  When you get off the pedal to coast or give the truck more pedal to kick in all eight cylinders makes sense that you would not hear a hum.

 

Zip,

Referring to the 4 cylinder cycle is exactly when it is happening.  Is it something that just needs to be accepted or is there a manufacturer fix for it?  Will it ruin engine?  Thank you

[The Zip]

My personal opinion, AFM works better with lighter vehicles (cars) vs heavy vehicles (trucks).  I don't think there is anything mechanically wrong with the AFM process and the fix would probably be not to use AFM with heavier vehicles.  Or maybe make AFM drop 2 cylinders vs 4 in heavier vehicles.  Expect what you hear to get worse with the more weight you put in or on the truck unless you change your driving style with a heavier foot to decrease the times AFM transitions.  The process of transitioning from 8 to 4 doesn't seem like it would ruin your engine.  In a couple of months I would be driving my truck for 5 yrs, it's performing better than day one.