2018 silverado 28000 miles

[James H morgan]

Bought my 2018 chevy new and always has had a rough ideal when stopped or in park. Took it to the dealer with no error codes they couldn't help me any ideas out there what i can do to fix. 

[rav3]

what engine?

[m3n00b]

Custom tune with higher idle speed.   Black bear fixed mine. 

[Ravenkeeper]

14 hours ago, James H morgan said:

Bought my 2018 chevy new and always has had a rough ideal when stopped or in park. Took it to the dealer with no error codes they couldn't help me any ideas out there what i can do to fix. 

Did the same thing with my '15, they told me that it was "on par."  It only seemed to idle roughly in gear, while in N or P it would purr nicely/perfectly.  When I bought my '18, never noticed the rough idle, like my '15 had.  What I have noticed is that I can feel the cruise control playing with the throttle more. 

[NWI Denali]

These LT engines seems to idle rough. I think a lot of it has to do with how low of an rpm they idle at. They almost shake and stumble like a cammed muscle car. I don't know if it's for fuel economy standards or what.

[M1ck3y]

I think gm tuned it to barely run while idling to reduce emissions. Plus with the massive runner's there's probably not enough air speed built up to mix with the fuel properly in the cylinder (at that idle speed). Higher idle helped mine