Does anyone know if this will work on 99 5.4 F250?I just want to be able to adjust timing & fuel a little.

 

It's possible, it lists f150 then it says 1996-2007 f250-f550, and right below that it lists 7.3/6.0 diesel, so taking all that it looks like it should. However, that's if I'm reading their application list correctly.

 

F-SUPER DUTY it should work fine. One thing i would do is make sure your X2 is updated with latest firmware and tune revisions. This can be done via www.sctflash.com... and go to Tech Support area