baffeled

i own a 99 pontiac grand prix all of a sudden it stopped running! i checked the intake manafold cleaned it checked all the sensors and changed 2 of them it started. got it home sat for 30 min went outside and wouldent start. checked for vaccume leek in the hosses no leaks. tried starting it wouldent start for some reason you can unplug the hose from the intake manafold and leave it connected to the fule pressure sensor and it idles high but as soon as i try to put the hose back on the intake manafold it dies seems like theres a clog but there isnt what do i do PLEASE HELP!!!!