My 89 f150, 351w, with a ZF 5 speed acts like it's hitting a wall at 3000rpm. I've replaced the distributor and it's adjacent ignition box, and throttle position sensor. I've verified my timing, there is no exhaust restrictions (verified with a vaccum gauge), the valves are not floating, (also verified with a vaccum gauge) and I have a consistent 30-35 psi of fuel pressure with the regulator and 40 without. The truck won't Rev past 3 no matter if it's in gear or in neutral and I have no idea why at this point other than a possible failed PCM, but it isn't giving me any signs of it because everything else electronic on the truck works

 

If you aren't getting enough volume of fuel , that could influence engine speed.

You didn't mention the fuel filter, has that been checked?

 

I changed the fuel filter, didn't change anything

 

Did you check the air cleaner filter and can you try running i without an air filter.? Have seen a restricted intake do this, worth looking into.

 

I have run no air filter and it made no difference

 

Some engines had a rev limiter built in, not sure if that is the case here.

Did you check the fuel pressure at 3000 RPM, if so what did you have?

 

Fuel pressure was about 35 psi at 3000rpm

 

Fuel pressure was about 35 psi at 3000rpm

 

Was there anytime it ran over 3000 RPM ?

 

when I got the truck the timing was way out of wack, probably about 40° retarded and the firing order I believe was wrong. It would rev to about 4 then