One problem related to tank assembly has been reported for the 1999 Ford Mustang. The most recently reported issues are listed below.
We were traveling northbound on i95 near the vicinity of edgewater, FL to st augustine, FL, when an 18-wheeler trucks tire debris hit underneath my vehicle. After the impact, I immediately opened the driver and passenger side of our car and a heavy burning smell invaded the interior of my vehicle. I stopped the car and my daughter and I checked around our vehicle and my fully-filled gasoline tank was leaking. I called 911 and left the perimeter of the vehicle for safety until the police and the fire dept arrived. If I had not opened my windows this leak would have ignited with the hot exhaust pipe and my daughter and I could have burned and our car.