I have a 95 Ford F800 that came stock from the factory with a 5.9 liter Cummins. Last night going down the road the truck was loosing power. Its max speed was 45 MPH when it will usually do 70. The filter was ok, but my oil pressure reading was down in the low range although it started high when the truck was first started and the oil was cold. The truck has 220k miles on it. Any ideas what my problem may be? Injectors? Lift pump? Loosing a clutch so it won't hook up? The RPMs just stayed low so I think it may be ijectors, but the low oil pressure has me bothered.

 

When you say the filter was ok are you talking Fuel filter or Air filter?

Do you have excessive black smoke, lack of air to mix with the fuel can cause black smoke.

 

I wonder if you lost your turbo? I remember a friend with a PS lost the hose to control the waste gate.... no boost.... had the truck loaded down and could hardly get it above 40.