1991 Chevy Cavalier idle surges up and down and bouncing oi

Got to be a vacuum leak somewhere, IAC is attempting to compensate but can't because of leak.

i have checked all over i can here like a pss pss sound but might be the exaust cause its not all the way tight at the flange

You can spray carb cleaner at suspected vacuum leaks, any change in idle is where the leak is.

ok i just did that and found nothing i need help

You need a scanner that can read live data. Watch the movement of the IAC (called "steps").

Most shops can generate smoke that will migrate toward the vacuum leak.

You could try a compression and cooling system pressure test.

But it could also be a leaking injector seal, intake manifold gasket.

Also scan timing advance.