rough idle at stop

[cquint]

I have a 2012 GMC Sierra 1500 5.3 about 70,000 miles. It just started doing this rough idle when you come to a stop in drive the rpms drop to about 500 and the truck feels its going to die, if you shift to neutral it doesnt do this. I don't know if its related or not but shortly before this I noticed the oil pressure was dropping to just about 20 when its up to operating temperature and you come to a stop. I have tried to find vacuum leaks, I have cleaned the throttle body, ran sea foam through the tank and the throttle body. I have changed the air filter, changed the plugs/wires and changed the maf.

[imcgyver]

Hello I had the same issue with my 2008 5.3 new throttle body did not help, what did help is I already had a Diablo Sport programmer to shut off my AFM I used it to up my idle speed in drive by 50 rpm now I do not have an idle issue any more, do not really feel the 50 rpm difference noticed the tac up a little but drives the same.
Ron


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