audio1

before bad gas my 1990 f150 ran fine after cleaning every thing up it still runs like it has no power sounds like missing some small back fire a little smoke at idle oil leak through valve cover but these problems didnt start until bad gas I changed wires plugs fuel filter,seems got worst two tanks later, still have same problem.

wde3477

Perhaps check your fuel rail pressure - maybe the fuel filter has clogged again? Another thought is that the pickup screen for the fuel pump has clogged.

audio1

Thanks for the reply by chance would you know what psi should be at fuel rail for an 1990 4.0 six ?

wde3477

Not sure of the spec'd numbers - suggest you're looking for something in the 30-40psi range. Suspect that too high pressure can cause problems as can too low - affects the calculation and capabilities of the injector pulse-width.

Good old Bill

Agree with wde3477, if ran OK before "bad gas" then change the filter, move on, thats what they are for. Relax and rethink, perhaps theres other problems.

cjwat24

+1 with the move on maybe check codes