Does anyone know the fuel pressure specs for a 92 B250? It is a 318 5.2

I have the gauge and checked it on the fuel rail at the schrader valve.

Just ignition on it reads 39 lbs. While running it reads about 35-36. Is it possible for a pressure regulator to be faulty and create erratic running while under load?

 

That pressure reading is right where it should be.

 

Have you done a tune up on this van? Is the terminals on the distributor cap brass or aluminum? If the latter get a new one with brass terminals. What plugs are you using and how many miles are on them?

Also have you changed out the fuel filter? I believe on your van it is just in front of the right side axle inside of the frame rail.