Everything...
One of the cylinders lost compression
Replaced numerous spark plugs, wires, etc.
Constant stall outs when she stopped momentarily, (from the cylinder not fireing)
I bought this car for 350 dollars I expected problems, but I also expected her to last longer then 3 months, one of my sparkplus literally exploded inside the engine, I've never heard of anything like that before... nor did the mechanic, she ran terrible the only good thing about this car was the interior which was amazingly well kept other than that, she was terrible.
You get what you pay for!
Yeah, when you buy a car for that cheap with that kind of mileage, expect to have some problems here and there.