rough idle went cold 88 ford van e 150 5.0 motor. egr or ?

 

How long since tuned up? Have you pulled the codes? I doubt it's the EGR, it would idle rough all the time, I would think. More likely plugs, cap, rotor, wires, fuel filter, PCV, something like that. Maybe the IAC is dirty?

 

what and where is the iac . where is it located on motor.

 

That's the Idle Air Control. It's a cylindrical piece attached to the side of the throttle body with 2 small bolts and has an electrical connector. It has a solenoid valve that regulates air flow when the throttle valves are closed. It can be cleaned with throttle body cleaner if it's gunked up.

 

As an addon to what c96drumm said, be careful cleaning the IAC.
Choke/carb cleaners will destroy the sealing o-ring.

Go on, ask me how I know LOL.

(Oh, the IAC is basically a controlled vacuum leak to attempt to stop the engine from hunting at idle.)

 

Oh, vacuum leaks reminds me:
they'll run like a dog if you have a bad vac line.
They go brittle & snap: I've had a fair few go on me & that makes it splutter and do all sorts of stupid things at idle: the IAC tries to compensate & amkes it worse!