Have you tried pulling codes?

 

Wheres the connector to hook up a scanner? And what scanner do I need?

 

All you guys need to check a few things and eliminate the possible causes 1 by 1.

First check fuel presure and to see that the pumps build 40psi(v8) or 50psi(I6) when vacuum is removed from the regulator engine running.

Pull codes, test connector on the drivers side inner fender, codes can be flashed on the CE light or pulled with a basic code reader. See fordfuelinjection.com for more details.

Check for vacuum leaks at the juice can on the passenger inner fender, the bottom rusts out on the metal versions.

Check that your EGR valve closes fully and doesn't leak and otherwise operates normally. Applying full manifold vacuum to the valve at idle should make the engine stumble. The valve should also be fully closed at idle, if it isn't when the normal vacuum line is attached the EVR is leaking.

Check for leaks in the thermactor(air injection) system. The V8's have a tube that runs across the back of the motor that will rust out or break, leaks in this tube or the attached valves will create a lean condition the will produce a very noticable and consistent stumble/vibration under load and heavy pinging once the engine reaches operating temp.. very noticable at highway cruise speeds.

 

This problem could be due to the TPS having an issue.
Also try unplugging the vacuum line from the EGR and see if it goes away. If it does, you need to restrict the flow thru it
https://www.ford-trucks.com/forums/1...ruising-4.html

Mines been doing it for a while, unplugged EGR help some.
Also if the TPS is bad it will run better if you unplug the TPS.

 

Yes and that should show up in the codes.

Well actually that means the valve is being held open when it shouldn't be so assuming the valve itself isn't stuck then the EGR vacuum regulator(EVR) is probably leaking or faulty and just needs to be replaced.

 

Thanks for the replies, I'll check it out this weekend and post what I find.

 

ill have to check that egr thing..

 

It was the fuel pump. Prob was so intermittent that it was hard to trace. Eventually the fuel pump just quit, that was it.