Jumping rpms wants to stall out

Question

I have a 1996 Chevy Blazer 4.3l vortec. I have changed the spider injection, the distributor, distributor cap, rotary button, crankshaft position sensor, camshaft sensor, new spark plugs and wires, and fuel filter. My mechanic found water in the fuel filter. When the car is cold, it runs fine, but as soon as it warms up the rpms jump and it wants to stall out,. I am at a loss at what it could be.