Sorry gentlemen i should have added some back story. being a new member i didnt know if anyone would give me the time of day, but thank you for the responses.
It is a 2007 LT, got it with 70k OG miles on it, 1 owner, carfax shows complete miles with all service being done at a dealer. It is spotless inside and out. the engine is clean enough to eat off of, even scoping the internal nooks and crannies where the dealer couldn't have been bothered to clean, its still surprisingly dust/grime free. What i did notice is it appears all the spark wiring is brand new, ac delco name brand, along with a new alternator. No other issues other than a weak AC and that annoying idle bump.
08- 6.2 denali xl somewhat the same. Our worktrucks are 6.0 and they do it also, You might have to accept that they dont like to idle at 600 rpm, Who knows? I sure dont, but as you have stated it does not affect performance so just tell yourself it's all the ponies wanting to get up to speed, lol.
and that would be a great thing to tell myself, but luck isnt exactly on my side. i fear simply going by that this will snowball into a larger problem. i dont really recall people having this issue and it going another 200k miles without it doing more damage. maybe it has, i dont know. my foray is motorcycles and my own V8 firebird that is 22 years old, still stock internally, and has yet to have an issue.
Also, check your motor mounts. Maybe your engine is idling normally and it’s just transmitting harshness through the chassis
i do not believe it is the motor mounts as my scanner shows that the idle rpms do drop. not by much. its about 580-600 give or take, then it will slump to 560ish and thats where you feel it.
Well, you might have a problem with the AC compressor. Pull the belt and spin the clutch assembly. Might be just the bearing or the clutch and bearing but if she's taking a while to cool the cab down...
If you have a bi-directional scan tool, check the commanded and actual position of the actuators to make sure they are working properly and of course, check for internal BCM and Chassis codes. An actuator can let too much heat into the cab delaying the work of the compressor to cool down the cab.
...ok im not 100 on what constitutes a bi-directional scanner. ive recently bought TOAD with the ELM327 and ive been ******* around while learnin myself with it. plugging into it it gives me the option of 2 ECMs, one with 50 PIDs and another with 9 PIDs. I used it to graph for misfires, it found none. not sure what yall get for fuel mileage but i average 14-17 at 80mph which is where it will spend most of its road life (welcome to Texas). Ive scanned everything that the little program will allow me to, nothing found. last reported DTC was 4400 miles ago, cant seem to figure out how to pull up what that DTC was. So if it sounded like i knew what i was doing electronically, im still on the learning curve.
