2014 gmc serria 6.2 rough idle

[Spencer copeland]

I’ve recently bought a 2014 serria denali with the 6.2. I’ve put about 10k miles on it so far and it’s got around 150k on it now. I’ve noticed that after the truck warms up it tends to have a weird idle that happens when I’m sitting at a red light for a long time or sitting in a drive thru. It typically gets worse the longer I sit there. It feels like the whole truck is shaking. Sometimes the rpm’s dip down and sometimes they don’t. The second you accelerate and raise the rpm’s it goes back to running smooth as it could be. I have alway run 93 octane since I’ve had it. I’ve used seafoam, gumout, injectron, all in the fuel tank. as well as replaced all the spark plugs and wires. It’s very annoying because it’s a nice truck that rides smooth I use it as a daily and for work towing a 14ft trailer and I wish I didn’t have to worry about the truck shaking when I stop. Any advice helps. Thanks