RPM issues

[jackraider]

I got a 2004 Tahoe 5.3. Every once in awhile if I get on it and come to a stop shortly after my RPMs will drop below average kinda like it has a after market cam. What could this possible be?

 

[powerhaulic]

idle air control servo sticking possibly

 

[Wake]

I'm thinking dirty throttle body. I've seen that before on a couple of my older vehicles.