It is normal per GM.

Most of us use tuners to raise idle rpm to 650 or so, which smooths it out entirely

 

^^^^ what he said.

 

Dat GM stumble idle doe

 

I've been dealing with a stumble idle in park and red lights. Sends shudders through the seat and door, but is way less noticeable than a true misfire.

I received a few responses on my last post taking about a "Lew" tune. I did some research and it looks like this is only available on the 22 Limited and older trims. Am I SOL on a 22 refresh? Or are there options to bump the idle up?

The truck only has 4300 miles on it, but I checked intake, filter and MAF sensor anyways. As you would expect on a new truck, they were clean as a whistle.

It has an appointment at the dealer soon for radio issues and I am going to ask them to check it out. It already had injector #6 replaced 5 months ago at around 3K which was causing a very noticeable misfire. Funny thing is, I didn't notice the stumbling idle until after that work was done.

Any recommendations are appreciated. I've done a lot of searching on this forum and most posts regarding the rough idle are 14-18 trucks. Couldn't find as much info on current gen 1500s with 5.3 Ecotec.

 

Any recommendations are appreciated. I've done a lot of searching on this forum and most posts regarding the rough idle are 14-18 trucks. Couldn't find as much info on current gen 1500s with 5.3 Ecotec.

I have a 17 (5.3). The idle is not as bad as you are describing, but I could watch it bounce at a stop some days. As a low mileage usage DD, I could afford to use premium. Has been fine since. Here is wishing you an inexpensive fix. Cheers.

 

Raise the idle? You’re SOL since GM has the ECM pretty well buttoned up and don’t think anybody has cracked the code yet.

 

HPTuners has already done it.

 

this wont help you, but in hot pheonix, i raise the idle on almost evervehicle i work on up to 725 rpms. It helps with the AC when sitting at a stoplight.

 

If all you want to do is bump the idle, you will REALLY have to want to do it, if you look at how much it costs even to do it on the early '22s. It'll be the same or more for your truck...

 

If it's still under warranty, make the dealer fix it to your satisfaction.

 

Thanks for all the input so far. Figured I would post an update after getting the truck back from the dealer this morning.

Earlier this week, I found a GM bulletin for the 19-21 trucks (PIP5798) which lists the exact symptoms I am experiencing. I asked the dealership to look into the vibration and let the service adviser know about the bulletin.

Got the truck back today. Dealer says they can't replicate, but the in and out milage is the same....so they didn't drive it. They say the PICO reading was max 3.5mg and average about 2.5 mg. Short of the 4mg threshold to take action. No CEL or stored codes. Dealer says they reset computer. Got in the truck and was able to feel the stumble at the first light I hit.

I honestly feel like I'm going crazy. I drove in a 21 expedition with 3.5 ecoboost to the dealer and idle is smooth as glass. I know its apples to oranges, but it really made the vibration in my truck more noticeable. I plan on running some injector cleaner through the next tank of fuel and maybe trying a tank of 91 vs the 87 I have been using. I heard of some people claiming this works.

The HP tuner seems like a nice option, but I am not keen on voiding my warranty yet on a 4k mile truck. Although I may do it sooner than later if this persists. Honestly having a bit of buyers remorse. Failed injector, radio issues and phantom shakes all in the first 10 months of ownership.