Toyota Repair: Trouble with Toyota SR5 Pickup

Question
I have a 1994 SR5 pickup 3.0 EFI. Troubles started about a month ago, truck would start in the morning. After running for a while, and shutting down, on trying to restart engine, would have to pump gas vigorously. Sometimes would start, sometimes would not. I would let the truck sit for half an hour to an hour at a time, then it would start up fine. As this problem got worse, the truck would hardly start at all. When I did get it going, it had no power at all, as if it were lacking enough fuel. Eventually, the truck would not run at all. I checked the fuel pressure at fuel pump, it only had 20 PSI. I changed the fuel pump with a new one, it still only had 20 PSI. When dead-ending the gauge, the pressure would go up to 43 PSI. I finally got the truck running by cranking the motor and tapping on the fuel regulator. The truck would only idle. If discontinued tapping fuel regulator, truck would stall. Prior to the truck not running, I have changed wires, plugs, the cap rotor, I have checked mass air flow sensor, is it possible that the problem could be the fuel damper on the fuel rail? I don't know what else to check. The truck ran absolutely fine before any of this occurred.

Answer
Have you tried replacing the fuel pressure regulator? the fuel damper at the end of the fuel rail doesn't have anything to do with pressure it's only function is to smoothen out the pulses from the fuel pump. Are there any diagnostic codes or is the check engine light staying on?