I just bought a 01 2500 with a 6.0. It idles low when I come to a stop for a few seconds before it can "catch up". I'm thinking clean the throttle body, so I looked at it to see how dirty it was. When I pulled the intake boot off the hole in the throttle body has a yellow rubber plug filling the hole. Everyone I've seen has just the hole. Has anyone ever run into this?

 

that was one of gms repeated attemps to fix that problem. you need to get some throttle body cleaner and a toothbrush and clean it out

 

So should I leave the plug in after cleaning it?

 

I'd try removing the rubber plug which should actually raise the idle a tad. Before tuning became common and readily available, guys used to compensate idle issues with larger cams by drilling out a hole in the throttle blade. (Definitely clean the throttle body also though)

 

Thanks for the help.

 

Make sure you remove it to clean it. I cleaned the front of mine and it looked good but when I reached in with my finger it was nasty. I removed it and cleaned the whole thing and it totally got rid of all my idle issues.

 

the yellow plug is in there from the dealership. at one point it was probably taken in for idle issues. what they did was open the set screw until it read a certain voltage and plugged the hole.