ok here is goes i have a 91 pu 4cyl with MPI and it was given to me, the thing started and runs but when i get to about 1/2 throttle it starts to die out untill the RPM's get back down to under 2000 and it pick back up untill 3500 and dies back down again. it does this driving down the road and in nutral. in nutral in i slowly pess the gas it makes it to 3500 and dies down to 2000 and climes back up. when it dies it sounds like its starving for fuel. here is what i have done so far. i have changed the plugs, wires, cap and roter, tested the fuel regulator i get 10 psi higher readings then the manual said i should have (32psi and idle and 42psi with no vacum and i had 45 at idle and 55 with no vacume). tested the ignition coil, tested the TPS also checked the timing . i am at my wits end, i cant figure it out. ooh ya and at idle it puuurrrrs like a kitten. what else can i do?? thanks.