i have a 1988 Chevy k 1500 with a 1995 chevy 5.7L engine in it, it's surging really bad, but only when i'm driving and my foot is just touching the gas pedal, but when I press it hard it acts fine, and after i push it hard and let it go fast it surges some more acting like it's going to stall out. I changed the TPS just wondering what else I can do to stop this problem... someone help.

 

Sounds like maybe the IAC