Won't start unless you push pedal to floor and then it will not stay running unless keep foot on gas. Have replaced plugs, wires, distributor, and pcv valve. Could this be a problem with fuel filter or fuel pump? Desperately need answer, this truck is my only transportation. Thanks

this is the same truck ...history: driving down the highway, truck was running good hear a pop under the hood truck cut off drifted and parked on side of road tried to start, it would turn over but would not run. had it towed and fix, mechanic said he replaced the ignition module, pcv and a oil soked air filter. ran good for a few months then started idling low around 500 rpms and would sometimes cut off when came to a stop but would start back up. ran kid to day care came back out to start, would not start, it sat for 5-6 hour tried to start again would run only if keep the pedal pushed almost to the floor. same mechanic got it back running. (can not remember what he did to fix it for the life of me) ran good for a few more months now idle was back down from 750 t0 500 or lower, coming to stops would cut off then start back up. last week (wed) coming up on heavy traffic, it cut off would not start back up, sat a few mins got it running by hold gas pedal down drove to closest turn lane, hold ind brake and gas pedal to some where around 1500-2000 rpm waiting for light, a very loud pop under hood she cut off smoke coming out from under hood, turned out to be steam the p. side of the radiator had blown out. finally got it towed home friday, sat replaced radiator and also replaced the plugs wires dis. cap and rotor button, took for test drive and ran fine check water/coolant level all was good. took it up to walmart came to a traffic light and it cut off and would not start back, pushed off the road (with help from a state trooper) checked under hood to fine the clutch fan had broke off the shaft, so figured she got to hot and cut off, when to closest auto parts and got the parts to fix (it had been atleast 2-21/2 hours, tried to start and would only start and stay running by holding gas pedal down alomst to floor. but did manage to get her back home. have check fuel filter good flow no gloggs and junk coming out when blowing air through it. no sure what to do at this point any help would be awesome. Thanks this is the same truck ...history: driving down the highway, truck was running good hear a pop under the hood truck cut off drifted and parked on side of road tried to start, it would turn over but would not run. had it towed and fix, mechanic said he replaced the ignition module, pcv and a oil soked air filter. ran good for a few months then started idling low around 500 rpms and would sometimes cut off when came to a stop but would start back up. ran kid to day care came back out to start, would not start, it sat for 5-6 hour tried to start again would run only if keep the pedal pushed almost to the floor. same mechanic got it back running. (can not remember what he did to fix it for the life of me) ran good for a few more months now idle was back down from 750 t0 500 or lower, coming to stops would cut off then start back up. last week (wed) coming up on heavy traffic, it cut off would not start back up, sat a few mins got it running by hold gas pedal down drove to closest turn lane, hold ind brake and gas pedal to some where around 1500-2000 rpm waiting for light, a very loud pop under hood she cut off smoke coming out from under hood, turned out to be steam the p. side of the radiator had blown out. finally got it towed home friday, sat replaced radiator and also replaced the plugs wires dis. cap and rotor button, took for test drive and ran fine check water/coolant level all was good. took it up to walmart came to a traffic light and it cut off and would not start back, pushed off the road (with help from a state trooper) checked under hood to fine the clutch fan had broke off the shaft, so figured she got to hot and cut off, when to closest auto parts and got the parts to fix (it had been atleast 2-21/2 hours, tried to start and would only start and stay running by holding gas pedal down alomst to floor. but did manage to get her back home. have check fuel filter good flow no gloggs and junk coming out when blowing air through it. no sure what to do at this point any help would be awesome. Thanks