Having a minor but irritating issue with my 2020 1/2 ton, 5.3. It is stone stock, up to an including the air filter, plugs, everything. The truck only has about 31k on the clock and I've had it for 20k of those miles. Ever since I have had this thing, it has had a light shudder at idle. Almost like a small vacuum leak in an old school carburetor equipped truck and there are no vacuum leaks that I've been able to find, hear or feel. I've had my son's $4k Snap-On scan tool tell me nothing is wrong, there are no DTC's set. O2 sensors switching normally, normal voltage readings and not running lean or rich, good fuel pressure, MAF sensor good, no wiring problems such as missing grounds or worn/frayed/chewed wires. Just can't find anything wrong.
I did make the mistake? of taking it to a Chev dealer. The SA told me that the idle is normal and if there are no codes, his techs would not be able to diagnose any problem. Glad it was a warranty deal because that is a completely unacceptable answer. Good thing I found out he has inexperienced mechanics before I need anything important.
So if any of you guys/girls have any input, I'd sure appreciate it.

 

A couple of things I would try that might clear up the "light shudder". One, purchase two 20 ounce bottles of Chevron Techron Complete Fuel System Cleaner and the next time you need to fuel up, add one 20 ounce bottle of the Techron to the gas tank and then fill up with a Top Tier 87 octane gasoline. Then drive around normally. When you need to get gas again, add the second bottle of Techron to the gas tank then again fuel up wiht a Top Tier 87 octane gasoline.

Your fuel injectors tips could have a buildup of deposits on them and adding the Techron along with purchasing a Top Tier 87 octane gasoline can remove the deposits. Continued regular use of a Top Tier 87 octane gas can assist in keeping those injectors clean much better than using a non-Top Tier gasoline of whatever octane.

Good Luck!

 

You can always pull off your throttle body and clean it. With the mileage being so new, I wouldn't believe it would be that so I'm not saying it will fix the shutter but I have fixed shutters with this before so its worth a try.

 

Thanks lonestarmechanic & chem_man.