Rattling inside right muffler (replaced with Flowmasters).
Burned up rear posi-trac (only one tire burns rubber now).
U-Joints needed replacement.
Speedometer cable was melted through.
Speedometer drive gear was also replaced, but still didn't fix the speedometer.
Replaced the convertible top cylinder.
Both of the outside door handles have broken and not many people can figure out how to use them (good anti-theft device).
Rear window shattered randomly.
Air pump locked up (I over-revved and it broke).
Fan clutch broke (replaced with electric fan).
Clutch & Flywheel replaced. It still slips on occasion and makes crazy noises.
Ashtray won't stay down (I hear that this is quite common in the '87-'93 Mustangs).
Fuel injector got crushed and was preventing the #3 cylinder from firing.
Headlight switch needed replacement.
Turn signal stalk needed replacement (twice).
Right rear window will not go down.
Innumerable minor faults/failures in the cabin.
Lots of squeaks and creaks due to a chassis that bends like a wet noodle.
The rubber loses tread at ungodly speeds, though it is probably driver-induced.