Not too many auto stores have an obdI code reader that they'll let you use for free, most will just have an obdII. However, you can scan for codes w a paperclip or buy an obdI reader on Amazon for like $30. Why not scan for codes before buying parts?
Also it's probaby condensation that you're seeing coming out of the tailpipes in the morning.
http://www.troublecodes.net/ford/
*Edit* never mind. Just noticed it was a V6/obdII. Go to auto zone etc and have them do a scan.