I have a 1992 E250 with a 5.8 and apparent fuel issues. I tested the fuel pressure and found 44 PSI without vacuum and 35 PSI with vacuum at a normal idle. Everything I have found with that kind of detail tells me I should be seeing about 39 PSI without vacuum and about 30 PSI with vacuum.

What should it be for my van? This sounds like too much variation. Since most regulators I have found cover a wide range of trucks, I suspect if I replace the fuel pressure regulator I will get 39 PSI. Is this enough of a change to cause a problem?