My '03 GT engine started running rough and threw me a trouble code- 1506 "DTC Definition not found, see ford SVC manual" Does anyone have a manual that can help me out? It's not in the "How to" section for for trouble codes! Thanks

 

I believe the p1506 is your IAC Overspeed(idle air control)
Try cleaning it or it may need to be replaced.

 

Great, Thanks very much! I think I caused that becaused I changed the gasket becauseit had too low an idle and it was stalling when I stopped too fast. I enlarged the hole and now its idling at 950-1000 but I guess the ecm doesnt like that either. Back to the drawing bourd! Thanks again!

 

Try doing a forum search on the code and you'll find some other people that had this problem, might give you some ideas on what needs to be done.