I started my Truck one day last week to let the AC run to cool the truck off before I put my daughter in. While my truck was just sitting there idling it seemed to start loping like it had a BIG cam in it. I checked the tac to see if the RPMs had dropped real low (it was normal) and even turned the AC off to see if that was the cause and it continued doing it for a while then just started idling smooth again. Since that day it does this intermittently when idling. There are no codes and I haven't changed anything in months. It really doesn't even bother me, i just want to make sure it doesn't turn into something bad. Has anyone had this problem and does anyone know the cause?

 

Maybe it's related to the Predator tune or a loose intake duct to the throttle body? You could always remove the tune for a few days and see if the condition changes at all.

 

I've had the custom tune for 6 months and it hasn't done this until last week. Also the intake is tight on the throttlebody. A friend said he thought there was a GM service bulletin on this issue but I have been unable to find anything on it.

 

a silly question but have you tried to idle it up a bit since the problem. could be you are idled down too low. just a thought.

 

iv got the same problem,only sometimes,with ac on and with ac off.mines is going in for other issues next week or the week after.hopefully they can figure it out without reflashing.