1991 2.6 4ZE1 Idles very rough...........:(

This is a '91 SpaceCab w/4ZE1 engine/5spd. I have replaced all the injector seals, vacume hoses but still the same. When I start the engine it revs up high for a couple seconds and then tries to stall. If I pump the gas once it stays running but I have to do this for 7 or 8 times before it settles down to a rough idle.