2020 GMC 1500 3.0l idle problem Ive tried everything....

[CFidu2023]

2020 1500 denali 3.0L LM2

 

For the past week it has been idling a little weird.

 

Intermittently it the idle rpm will fluctuate from 300 to 500 and I get a vibration in the steering column.  It has yet to stall. 

 

It doesn't always do this.  Sometimes when I pull upto a stop it idles perfectly, sometime it does idle a little rough. 

 

The dealer says they cant find anything wrong with it. Ive done the following. 

 

Oil and filter change

 

Air filter change

 

Fuel filter change

 

Ran diesel kleen through 2 tanks

 

I also tried the propane enrichment to find a possible vacuum leak

 

Disconnected the battery and reconnected it. 

 

Nothing...

 

The dealer as I said has found nothing wrong with it.  No codes, no CEL nada... 

 

Its almost like when the Idle Control Valve in a gas powered engine is bad.

 

Its acceleration seems to be fine. Just does this damned idle thing every now and then.  Really annoying.  

 

I did hit a pothole around the same time this started.... It might be a stretch but maybe something is loose that Im not aware of???