Problem with 1990 stalling after engine is warm.

My 1990 3.1 runs fine when it is cold. After it is driven a while and I shut it off and then come back to go somewhere else it acts like it isn't getting any fuel. Sometimes if I keep pushing the gas pedal it will come out of it a run fine again. I had a code 33 so I changed the MAP sensor then I changed the crank shaft sensor but neither helps. Not sure what to do next. Any help would be appreciated.