Engine rough

[rjr]

My 2015 Yukon 5.3L, at about 40,000 miles, started idling roughly when stopped and in gear. Smooth in neutral; smooth on the road. Now at 49000 miles, seems to be getting worse. Dealer tells me this is usual and not repairable.
Anybody else have this issue, or get that tale from the dealer?

 

[swathdiver]

Well, was the dealer kind enough to tell you what was not repairable? Is the idle a little low? Throttle body might need cleaning or it could need intake gaskets.

 

[Miami-Dade]

Mine has had a rough idle [every once in awhile] since day 1. It is not that often so I am not concerned with it. My 2015 plus rentals did the exact same thing. The strange part is once I get out of South Florida it idles as smooth as silk. Even waiting 90 minutes or more to get into the Lincoln Tunnel it is smooth as can be.

I am thinking the gas has a lot to do with it. I have 40K miles now. I generally burn 87 Mobil where ever I am. Higher octane did not help.

 

[k-mart]

If you're not worried about warranty, get a tune. If you are, wait until out of warranty and get a tune. I don't know if it is an emissions thing or a combination of the flex plate/torque converter used, but the idle seems to be about 50rpm too low. Bump that idle up just a bit and everything smooths out.

 

[rjr]

I was under the impression that idle is not adjustable. When idling rough, tach seems to read about 450, which to me is low.
With regard to the SOuth Florida comment, here in Virginia it's been very hot for the past month or so.

 

[swathdiver]

If memory serves, the idle should be at about 600 rpms in gear. BlackBear bumped it up to 50 rpms to avoid "stumbling" on mine. Check for any loose connections between your air cleaner and throttle body and inspect the TB for fouling.

 

[rjr]

For cleaning or inspecting the throttle body, how does one apply power to the throttle motor to open it, when the vehicle does not have a key to turn on?

 

[Miami-Dade]

With regard to the SOuth Florida comment, here in Virginia it's been very hot for the past month or so.

I was in Emporia Virginia last night and it was miserable.

 

[dbbd1]

I was under the impression that idle is not adjustable. When idling rough, tach seems to read about 450, which to me is low.
With regard to the SOuth Florida comment, here in Virginia it's been very hot for the past month or so.

It is adjustable, through black bear or handheld tuner.

 

[Doubeleive]

For cleaning or inspecting the throttle body, how does one apply power to the throttle motor to open it, when the vehicle does not have a key to turn on?

you can move it by hand it has a spring inside and just returns to the closed position when you let go of it, just don't be rough with it when cleaning treat it gently.