Why will it not accelerate correctly?
1988 E-150 with 302 Multi-port, new plugs, new fuel filter, new air filter, no cat. converter, fuel press. in rail is 37 p.s.i., MAP good, has a auto. trans w/overdrive... in overdrive it will hardley maintain 55 MPH... if you come to any incline at all... hard to get over 35-MPH.. put it in drive, maybe a little better, but not much... LACKS ACCELLERATION AND POWER...
...again, am like a broken record here, it's the EGR valve, what takes exhaust gas and puts it into the intake manifold under decel and/or specific conditions, gets messed up with carbon and frequently has a leaking vacuum control hose~ take it apart and de-carbon it, or buy a new one~
Could be something dealing with the ignition timing. Where it will run good but no power. Vacuum advance if it has one.
Did the cat melt down? If it did then it may have plugged the muffler. Have you had an exhaust backpressure test done?
Search Ford E-150 Questions
Ford E-150 Experts