You'll need to get your 1993 Ford F150 diagnosed by a certified smog check
repair center. The reasons your Ford failed the smog test are many. Without
a hands on diagnosis it will be impossible to tell where the problem is.
You may want to have one of our online smog technicians look over your
Ford's failed Vehicle Inspection Report (VIR). Follow the link below...
http://www.smogtips.com/smog_evaluations.cfm