Strange Random Low Idle

[Jordan836]

Alright so this weekend I cleaned the MAF to see if that would help and it seemd to help for a little while it idled fine but then it seemed once I drove it for about 15min it seemd to go back to idling around 500-550 rpms. I got home and when I was in the drive way when I had it in gear I was just playing around with some things and with the windows up all the way when I pull up on the window switches the headlights dim and the rpms go down even lower and I can actually hear the engine change rpms then you let go of the window switches and the headlights are normal brightness but the idle still goes back to 550rpms which I think is low but correct me if Im wrong. But after all that I thought maybe it had to do with the little stero system I put in because it started idling low a few days after I put it in. The stero system consists of a Pioneer AVH4100dvd a rockford fosgate t-400 amp a 12in sub and 4 gauge power wire that goes through the firewall over to the battery with an inline fuse and fuse holder before it attaches to the battery its pretty simple. But I thought that since my the truck started to idle low not long after I hooked the system up maybe that was the issue so I disconnted the power wire for the amp from the battery and started the truck up while it was still warm but it didnt make a difference it still did the same thing when I pulled up on the window switches and still idled low. So could this possibly mean my battery is bad and just doesnt have enough juice to power everything it has to power and that might be what is making my truck idle low? Having the heat on all the time wouldnt really make a difference would it? Its gotten cold here in CT and ive always got the heat on and right around the same time I started using theheat more is right around when it started idling low but I dont really see how that could make a diference. And I had this same stero system set up the same exact way in my old 5.3 Silverado excepet I had put a brand new optima yellow top in it and I have no problems at all so I dont see how it could be something with the way I have my stero set up its gotta be the battery itself Id think. But just for good measure what should is the ideal idle RPM for these truck? As of now once the truck it warmed up it idles around 700-750rpms in park then in reverse of drive it goes down to around 500-550rpms. I appreciate any thoughts on what might be going on I really need to figure this out ASAP because im making the drive from Connecticut to Florida in a couple weeks to ride dirtbikes down there for the winter so Id really like to get this figured out before I leave that way I dont have to deal with it down there! And if its something I can fix easily myself id much rather do that than bring it to the dealer and have them figure it out!!

[alex.t]

first off normal idle is around 500-600. secondly all of the these trucks lights dim when you hold the window up. you could give it a try and pop a optima red top in there or yellow top dont matter. have you cleaned the throttle body out ?

[Jordan836]

Ya I cleaned the throttle body and MAF. I"ll just keep and eye on it and see if it does anything strange again. Thanks for the help!

[holdenhunt]

I have this exact same problem. I first started to notice mine would act up after I switched over to a BBK 80mm throttle body, exact same symptoms. I have been battling with this problem for a long time. I have a bullydog monitor that reads and clears DTCs and my truck will sometimes throw itself into limp mode. The code it sets off says that I have a problem with the throttle body actuator motor. Long story short I ended up raplacing the motor with another one from a salvage yard because it is impossible to buy the motor only, Chevrolet does not have a replacement part number for this so you either have to buy the whole throttle body or do what I did. Anyways, after I installed the new motor the truck ran like a champ with no problems for 4 months until now..it is doing the exact same thing again! I dont know what the deal is with these faulty motors however I do know that if your truck goes into limp mode then this is likely your problem. Also before discovering this I cleaned the MAF, filter, and throttle body itself which did not help at all.