85 Fiero RPMS jump after warm

I have a 1985 Pontiac Fiero 2.8L v6. Recently bought the car.

The car fires right up, but as soon as it gets warm the RPMs begin to jump all around. (within 1000).

I have replaced:
Fuel filter
Plugs, wires
Distributor cap
Rotor button
Ignition module
Ignition coil
Idle Control valve
Coolant temperature sensor
Added some iso-heet water remover to gas, thinking i maybe had some gas in the tank.

Also, when it begins doing this, if I come to a complete stop the car will either die, or sound like its about to die. If I throw it in park, it idles at about 1500. I feel like I don't have a lot of power.

Thinking about setting the timing on it again tomorrow, however the catalyst sticker has been ripped off so I don't know how much to advance it.

Any information you have will be greatly appreciated!

ps

Auto parts store had me remove the ignition module about a week ago, and they tested it and said it was fine, but there was a lot of corrosion on it. After putting the OLD ignition module back in, the car worked fine. I had thought it was the corrosion on the module causing it to act that way.

Here i am a week later, having the same problem, so naturally i thought that it was the module. Replaced that first, then all the other things. I had thought that when removing it for the auto parts store, my arm had hit up against something else, or a wire, causing the problem to go away.

My thoughts:
EGR valve, or tubing?
Fuel pump

I hear a hissing coming from the engine, vacuum leak?

Have you found any error codes?

UPDATE::

I replaced fuel pump, sealed up the EGR leaks and problem was still there. It ended up being the MAT sensor (yes MAT, not MAP). It screws into the air filter housing.

Hope this helps other people!!!!!


also, anyone know how to adjust a TV cable? Mine doesn't have the ratchet like the haynes manual says it should. I did have one like that but had to return it because it wasn't near long enough.