i have a 1993 Jeep Grand Cherokee Laredo 6-cyl 4.0

my car wouldnt start the other day, so i assumed i needed yet another ignition coil....that would make 5 of them in a year (what would cause that?)

well i put the ignition coil in, and it started and ran fine, until i turned it off, then it wouldnt start again.

i changed the plugs, wires, dist cap, rotor button, it started and ran fine until i turned it off, then it wouldnt start again.

i changed fuel filter, and it started and ran fine, until i turned it off.

after i turn it off and try to start it again it sounds like it fires a couple times, then it may half-start like its firing 3 cylinders or running out of gas. i dont know what else it could be except maybe the fuel pump. but is it likely for a faulty fuel pump to work and then not work and then work again?

ive been fighting this thing for 3 days now and i dont know what else to do.