I just bought a 03 f-250 xlt extended cab short bed v-10 4x4 with 135,000 miles on it. I had a dealer get it for me and it is a nice truck, the only problem is that it runs rough at idle and surges when at 40 mph and when you try to gradually get to 55 mph. If you baby it around it misses real bad but if you give it gas it runs real hard. The check engine light is not on. Anybody know what might be causing this. The truck had been sitting on a lot in Iowa for 3 months until I bought it. Any info would be helpful, thanks

 

Pull one of the spark plugs to see what shape they are in. Theres a good chance the plugs were never changed in the truck.

The gap specs are .053"-.056".

It would be a good idea to clean the MAF sensor and replace the the fuel filter. The IAC elbow could be cracked also. Other guys here know more about the IAC stuff than I do. They will chime in.

 

I agree with DKF. Check all the normal maintenence items. Check for a bad COP and the plug boots ae well.