Toyota Repair: fuel problems, intake hoses, 22re engine

Question
i have a 1991 toyota pickup with the 22re engine.somtimes when i would turn my truck off i would try to start it again and it would run for a few seconds and die.it would do that a coulpe of times and then start and stay running,i would have this problem about once or twice a week for a coulple of months.then all of the sudden it would not stay running.it starts every time i turn it over but it will only stay running a few seconds.i put a new fuel filter on and that did not work so i put a new fuel pump on and that did not work.i took the throttle body and evrything off to make sure it was all clean i blew it all out and made sure i was getting fuel to the fuel rail which i was.i put everything back together and it is still doing the same thing.i am lost could you please help?

Answer
It seems there is an intake air leak, have you checked to make sure there are no leaks in the intake hoses from the air filter over to the throttle body? Also check for any large vacuum hose leaks under the intake manifold and the PCV hoses on the valve cover.