Rough Idle = New Motor Mounts?

[lapoolboy]

21 hours ago, Jason Broswell said:

I have had a 14 Sierra and a 16 Sierra and both have had idle issues. I installed a catch can on my 16 to stop the crankcase oil vapors from blowing back into the intake abs caking up the valves and throttle body. Odd thing in response to your post 

 

had my oil changed last week notified them of some odd squeak I had sounded like body flex or body mounts. They determined it was motor mounts. They had to order the parts and would replace under warranty. Today I picked up truck after they had it all day yesterday replacing the mounts and my rough idle is gone. 

 

So I would say they are correct in the rough idle being motor mount related. It had A rough idle when I took it in they changed mounts and. Now smooth idle it’s so nice too such a relief 

That service advisor needs to take a remedial spelling course.

[Nasty]

Hpw are you guys cleaning your maf sensors?

[Bob2C]

I too am having same issue on my 2018.  So I posted on another forum and someone replied with body mounts not being torqued correctly. Never thought about that.  Here is the link https://chevroletforum.com/forum/tahoe-suburban-25/2015-tahoe-idles-rough-shakes-85174/#post432688

[L86 All Terrain]

On 10/17/2018 at 3:30 PM, Nasty said:

Hpw are you guys cleaning your maf sensors?

[Bob2C]

Truck only has 12k miles on it. I pulled the sensor just to check and it looks spotless. So that’s not the problem


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[Bob2C]

So I finally took my truck back in to the dealer because it had gotten worse and explained the situation, showed them the tsb for the vibration at idle. Tech confirmed the issue. They have been working on it all day with sensors trying to get a reading. They called and said they are having issue because of the aftermarket exhaust throwing the reading way off and need more time. I told them take as long as you need. At least they acknowledged a problem. That’s a start. We shall see where this goes. Anyone else run in this issue with the aftermarket exhaust? GM sells the Borla system.

 

Update: After 3 days at the dealership they confirmed motor mounts are bad and need to be replaced. Dealership said it’s the first one they ever did. We shall see how this turns out.

 

What I don’t understand if this is a big enough problem to warrant a TSB, how could it be their first one? Do people not care they just paid 50k + and the car idles like shit? I just don’t get it.

 

Final update

 

Got the truck back. Nice and smooth idle. Mounts were the cause so if your experiencing this issue take it in and mention TSB 17-NA-166.

 

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