Engine is not smooth at idle.

[Robert Meyer]

On my 2019 GMC Sierra 1500 6 cylinder gas the engine is not smooth at idle. Any input on my problem. Thanks

[ericarenee]

The 4.3 engine has been this way from its inception. Its better now then previous years. I am not a car person but it has something to do with a 90 deg angle on the cylinder heads kept from the 350 engine when they  at GM Decided lets just lop off two cylinders and call it a v6..  

 

My explanation might be wrong ( I am not really a car chic) But  i have had lots of  4.3 engines and its just what it is.. the new gen seems be  way smoother. 

[BlancoSilverado]

Try a full tank of 91 octane( not octane booster, highest at the gas station ) and see if it runs smoother. I run 89 octane in my 5.3L because it didnt run that smooth  with 87(at least it felt that way). 

[Robert Meyer]

I did rum 93 octane for 3 tanks no change. 

[tlaw91]

Fuel won’t change ur issue

Problem is you have a tiny unbalanced direct injected motor mounted to the strongest frame GM has ever created

So it’s a damn tuning fork

It gets into a groove and makes that joker shake like a misfire. Totally normal. You can however loosen the trans mount and both motor mounts when the truck is hot hot, then brake torque the truck a lot, then torque the bolts back down to ‘settle’ the powertrain.


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