Engine Revs/Car Moves On It's Own

[abarthle]

Hey guys I got a 94 Firebird Formula, i've got a interesting little problem that even the mechanics don't really know (or want to deal with). Every once and a while I start up my car the engine revs up to about 2k-2500 rpm and slowly comes down. Just recently I was sitting at a red light behind someone and my engine started reving on its own and starting to move forward while I had my foot on the brake. I had to think quick and step harder on the brake as well as throw it in neutral so I didn't hit the car in front of me.

Any thoughts/ideas as to what my deal could be? Loose timing chain perhaps? a mechanic said that most times the water pump leaks on the distributor and that causes problems but he didn't really look at the car he just gave his best guess. Any help here would be great!

Thanks

[00z28bubba]

maybe this might help, on my old 84 regal i had a vacuum leak and the idle was easily like 1500 rpms. found the leak and near 500 rpm idle returned. but it was a base model carbed 3.8 not a sfi 5.7. just a thought.

[94BC4]

I had the same trouble I found that my elbow to the Throttle body was cracked and sucking dirt.

[basballny2]

MAF?