Really rough idle?

At4lance · Jun 30, 2025

I have a 2019 at4 with the 6.2 that has 160,000 miles on it. I’m having problems with the idle as it idles really low. It constantly goes so low it almost cuts out but always bounces back up. Maybe it’s not a major problem just really annoying as the whole truck shudders whenever it happens. Any advice or ideas what it could be? Thanks in advancd

gemarsh · Jun 30, 2025

Welcome.

Sport0519 · Jul 1, 2025

At4lance said:
I have a 2019 at4 with the 6.2 that has 160,000 miles on it. I’m having problems with the idle as it idles really low. It constantly goes so low it almost cuts out but always bounces back up. Maybe it’s not a major problem just really annoying as the whole truck shudders whenever it happens. Any advice or ideas what it could be? Thanks in advancd

Does this only happen when the engine is cold, or does it occur regardless of engine temperature? If this occurs regardless of engine temperature, I would check your air filter and MAF sensor and make sure both are clean. If this only happens when cold, I know the previous generations of the LT/LS engines are famous for intake gaskets going bad and causing this. Once the truck warms up, the rough idle usually goes away (but not always).

strmtrpr · Dec 3, 2025

i have a 2019 6.2l. this is what I just did that helped a ton. do a carbon cleaning with a vacuum hose using crc intake and turbo cleaner. get MOA products for your crankcase and gas. I also just changed plugs and wires. im at 80K I also had rough idle start and everything in between. our engines are gdi engines meaning the carbon doesnt get burned off like a direct injected engine. this will help. just follow the directions and watch videos of people doing it. i dont feel my engine at all at a stop light.

get ready for tons of smoke to come out when your done. thats the carbon hitting your cat at very high temps and dissolving.

and like above, check your maf and clean it. especially if you have a oiled filter.