Pretty much like what the title says. 2004 SS Supercharged L67, about 134000 miles. When it idles the rpms will shoot up from anywhere from 500 to 4000, and it will do the same while driving, making the car accelerate. Any ideas as to what this could be? It does have a vacuum leak that needs to be fixed and I wonder if that may hav esomething to do with it.

 

A vacuum leak can cause an erratic idle as you describe. I would eliminate the vacuum leak and see if that resolves the problem. If it doesn't I would check the MAF sensor wiring. Still not fixed? Test and clean the MAF sensor. If the idle is still erratic I would then check the IAC.