Had a new problem surface today. When I start my truck cold it will die right away unless I hold the gas pedal down, in which case it will rev to wherever until I release the pedal, then it dies again.

Once everything warms up the truck will idle, but at about 400 rpm instead of the 550-600 it's supposed to be at. It runs and drives fine everywhere except at idle. No SES light, and I swapped out the MAF sensor already, no help.

Anyone have any ideas for me?

 

Try cleaning the throttle body. Especially if its drive by wire. A dirty throttle body can contribute to low idle and stall at idle.

 

clean the throttle body

 

What's the best thing to clean it with? Can I just use 409 or something?

 

You can get throttle body cleaner at just about any parts store (comes in a spray can like brake cleaner). I use BG Induction cleaner that I get at work that's really good. You want to remove the air intake hose and open the throttle blade and spray in there real good. I usually take a rag and wipe down the throttle blade and body to get all of the carbon out. If it's really gummed up, you can remove the throttle body (or just unbolt it) and get it from both sides.

 

I pulled the TB off and looked, it didn't look too bad, but I will get some cleaner and do it anyway.

Got a vid of the truck idling too, in case it would help. Quicktime format, 9.25mb.

Another thought...could it be a bad idle air control valve/actuator/whatever it is?

 

Check and see if your battery terminals are corroded. If they are, clean them real good. I had a similar problem as you stated. I cleaned my up and the problem went away.

 

I was just thinking the same thing...seems possible. Does it run fine otherwise? Good while driving, just won't idle...maybe a bad IAC

 

Yep, swapped it with the IAC from our 00 Burban, now my truck runs fine and the Burban is funky. Found it! Thanks guys.