its in all likelihood a cracked exhaust header.. the a/c has a drain line that is directly above the header and drips right down onto it often causing it to crack.. it can be removed and welded or replaced oem which costs alot or replaced with aftermarket "shorty" headers (same size as the exhaust manifolds on the car)
2003 3.8L V6 4R70W
Windstar Upper Intake with cool-air intake, MAC LT headers, BBK O/R H-pipe, and flow 40s, SCT tuner, FRPP Alum. D/S, 3.73 gears, Auburn HP limited slip, and Team Z LCAs, Eibach sway bars.
Best 1/4 time: 15.036 @90.92mph, 2.148 60'