OK guys, I'm going to give as much info as possible here.

Mods are in the sig, recently pulled off the intake to block off the EGR valve. While in there the TB was all cleaned out and the IAC was replaced with a new piece.

Now the idle is high and at times the car will drive itself. Also, if going anything over 60mph and you put it in neutral the rpm's won't drop, they stay at around 2K unless you blip the throttle a bit and it sometimes drops.

Now, I don't know all of the settings in the chip(previous owner burned it). My question is this. If he tuned the car with a gunked up TB and an IAC that "may" not have been 100% could the tune be off? One other theory that someone I trust says the regular ATI bypass valve sucks and that the boost is pushing through the throttle blade. Now in theory that makes sense but why would that happen now? Is it because everything at the TB And EGR are all tight and sealed?

No vacuum leaks, nothing out of the ordinary is visible.

I'm leaning towards the chip needing to be tweaked but I really don't know enough to argue. I don't want to drop $400 on a racegate if that's not the problem.

Any ideas or suggestions? The problems are intermittent but it's getting a bit worse, it seems like hitting the throttle for a second will bring the rpm's down...however it doesn't help it all the time. It also seems to do it more frequently after getting on the throttle/driving hard. Sometimes I really have to fight with the brakes to get the car to stop.