My 92 F250 7.5 ltr 460 4x4 is idling really rough. I have changed the map sensor and idle air control valve and it still idols rough. What else could it be?

 

What one person describes as a rough idle , another person might describe as a slight misfire. SO,,,,,,,,we might need some addl info.
Does the idle smooth out if you raise the engine speed a little? If it does , that could indicate a vacuum leak that the system cannot compensate for at idle.
If it does not smooth out , it could be a slight misfire, in which case further checking is required. Sometimes a broken /leaking vacuum line can produce this symptom.
Did you do a thorough visual inspection to see if anything seemed out of place or appeared wrong?

What kind of maintenance has been done , when, and how many miles are on the odometer?
All these things can influence if problems come up.