Just about everything.
The engine had decent power, but if only the transmission was worth a bloody penny. I spent a whole lot of money fixing this car, and can't even remember everything that has gone wrong.
The paint job wore away from the front in no time.
Don't ever buy a Corsica. Some of the newer ones are quick, but everyone I know who has one including myself had to spend too much for too little a car.
It's not very comfortable or attractive, and definitely not reliable.
Many cars have trouble after the 100,000 mile mark. I would have to say that there were problems that the previous owner didn't take care of as to why all these problems exist.
I think that their might have been other existing problems that lie beneath the surface, so they were hard to detect and that, in turn, ended up costing the majority of the money you spent.
I completely agree about never buying a corsica. I have a 91 LT model, and though it has not failed me yet, it only had 18000 miles on it when I bought it three years ago. I can already feel the transmission starting to slip, and the trunk leaks from an undiscoverable source. The car has NO power, but at least it only takes ten bucks to fill it up.