1995 F-350-351W Engine Stumbling

I have a problem with my 95 F-350 lurching and/or stumbling during driving. Wires, plugs, cap, rotor have all been changed, taken to the shop and throws no codes. Any ideas out there? Any help would be much appreciated.

Use a can of carb. cleaner and spray along the intake manifold. If you find a big vacuum leak the engine will smooth out immediately. A pickup going bad in the distributor will cause it feels like the engine shut off and restarted. A module on the side of the distributor can be tested free at Advance or Auto Zone. A leaking EGR valve will cause rough running even stall the vehicle.
Disconnect the vacuum booster and put a bolt in the hose. If the engine smooths out buy a rebuilt vacuum booster. Check the timing an engine out of time will run rough.

Fords do have problems with the IAC motors.Unbolt it with plugged and have someone turn the key with the engine off,it should move.Turn the key off,it should go back where it was was.If this is the case,clean it first with carb cleaner or replace it if cleaning it does not work.It run and quit with the brake boster hose off.

At all times? Under acceleration? Off Idle? Cruising? That info might help out a little as well.