The car started loosing power but no codes. It kept loosing acelleration especially up hills. I took it to 2 shops so not to throw parts at it, but no diagnosis. Same thing happened at 2 transmission shops and 2 exhast shops, nothing found.Then it spent 8 days at the hyundia dealership, still no problem found. So I repaced timing belt and tentioner crank position sensor, radiator thermostat, transmission fluid, coil packs, plugs, wires gas pump , fuel pressure regulater,, Maf sensor, throttle position sensor, egr valve, cleaned fuel injectors, checked and cleaned all vaccum lines, checked fuel pressure, Rechecked cat at exhast shop, fuses battery cables grounds , ecm check. The reason we bought this car was because of its good ratings, awsome even.This may be the worst car ive owned.i wpould have listed all the ptonlems seperatly , like you asked, biut im too busy trying yo figure out the problem with this awesome car! Maybe other people just get tired of these cars and give up, because ive seen alot of other similar complaints with this car.