Nissan Repair: 92 pu cutting out under load, throttle position sensor, fuel inj

Question
I have a 92 pu with 3.0l fuel inj and 225,000 mi.
Lately it has been cutting out under a load ,sometimes it clears up most of the time not.We changed the cap,rotor,plugs,wires and the distributor,even though there was no sign of oil on the optics.Changed the fuel filter and tested the psi regulator.Had 34 psi at idle but went up to 40 psi under a load.Had 43 psi with vacuum line disconnected.Should the filter maintain 34 psi when not running.
Can you help please?
Thanx chris

Answer
Chris,

Check the intake hose between the throttle body and the air meter for cracks.  Also, make sure there are no hoses that are loose that connect to it.  If you get unmetered air the truck will fall on its face.  When you said under a load that is when the engine will pull on the hose, when the engine torques.  Also, you did not mention if there were any codes set.  Probably not since it is not mentioned.  So, I feel that you have a bad air meter or a cracked intake hose.  Since you replaced the distributor and the fuel pressure is normal you should not have problems with these.  Yes, the fuel pressure will be maintained for a time when you cut the engine off.  Now, if it drops to zero immediately after shutting off the engine would mean that you have an injector leaking into one of the cylinders.  If you pull the plugs you should see if one or more is really black would be a give away to the cylinder that is getting too much fuel.  One last thing would be that the throttle position sensor having a spot where it looses contact.  If you drive and the truck falls on its face at a certain position of the throttle that would indicate this condition.