Everything. In the span of 3 years that I have had the car, not a single thing has functioned as it is supposed to. In addition to the general problems that everyone has heard about (rattle in the hatch, clutch going, etc.), I have had to take my car back for several other reasons:
1. The paint on the spoiler peeled in less than 1 year which the warranty did not cover.
2. The interior dome light doesn't always turn on.
3. The performance tires wear quickly.
4. The check engine light constantly goes on.
5. There was a recall for a cracked gas tank.
And many other minor things that were covered and repaired by the dealer, however just because the warranty is good (not in my case) you still need to spend time and inconvience yourself to bring your car back to a bunch of guys that know you on a first name basis, of whom many are just as annoyed as you are and are tired of fixing problems. The group, understandably becomes less than friendly and the environment is just not comfortable.
WARNING: don't buy Hyundai, they suck.
I'm sorry that you have had such bad luck with your Tib. I have had mine for 2 years, the only prob I had was the brake shoes fell apart, but they fixed everything. not a single penny out of my pocket!, I truly love the car and have never been as happy with any other vehicle (Tiburon SE 5 speed!)
I have owned my Tiburon SE 5 speed, for a year now and I the only thing that has gone even a little bit wrong with it, was that the back wiper loosened off and didn't snug the window, but I fixed that with a little tightening of the screw. True the Factory tires did wear quickly, but to tell you all they aren't the best "performance" tires I've ever seen. My Tiburon is a solid car and has yet to fail me, in my opinion a great car and if I was asked YES I would buy another.
I bought my 1997 Tiburon right off the show room floor. I am now close to 118,000 miles. I love my car and wouldn't trade it for another! No real problems.
Sorry to hear about the problems you have experienced with your Tibby, however problems only arise if not maintained and serviced regularly. Tiburon Fx is very reliable, not matter how hard to drive her. This car has porche spec on the suspension, and tiburon is solid all round. Have you seen the crash tests on this car, she is built solid.
Sorry, to hear about the problems you encountered with your Tiburon, problems like these arise when you don't look after them ie servicing them regularly like any other car. These cars are built solid, they have a stiff suspension with porche spec, which handles well around the twisties, and for an entry level 20l DOHC, they have a lot of grunt. These cars do not have a good launch, like the Mini Cooper S and the M3 etc, but they can swim headon with these high performance machines. So if you want a car that handles well, looks good, and can reach 200km with no effort at all, Tiburon is value for money. Hyundai did well with Tiburon 1st generation, 2nd and 3rd. Well done Hyundai, you guys make the best cars.