I got a 2002 E150 V6 that is running very rough in the lower and middle RPMs but really strong in the upper. Had a busted plug wire fixed that but still really rough. Trying to get it ready to sell. Checked tranny and plugs and wires but still no luck what else should i check.

 

Did you replace the plugs and wires or just check them?

Both are known to cause just what you describe.

If they are several years old and/or past 60-70 K miles, I'd replace them.

 

If the plugs & wires are good or changed & still runs rough you might want to check the coil pack I have gone through quite alot of them on our fleet trucks.
Also you can look to see if the intake runner control rod clips are broken. These clips are on the back of the engine they are white in color & the IRC rods clip into them. They are made out of nylon plastic & get brittle from the heat of the engine. BAD DESIGN!