Hyundai Repair: fuel pressure regulator, fuel pressure regulator, crankshaft sensor

Question
I did a diagnostic on my 2000 Hyundai Sonata 4 cylinder 2.4L and it said I needed a new crankshaft sensor.  I ordered the part and was told not to attempt the repair myself because if the timing were off just a bit it could have serious reprecussions and do internal motor damage.  So, I towed my car to a local Hyundai dealership and service center where I had them install a new crankshaft sensor along with the blade, tensioner and balance belt.  The service center called me earlier today and stated that the car is misfiring and that there is fuel leaking into cylinder #1.  During a diagnostic, is this something that would have come up if it did indeed need replacing?  If the vehicle were timed improperly and then ran, could that cause the fuel pressure regulator to need replacing?  The vehicle had no signs of flooding prior to replacement of the sensor and the gas mileage has not changed from the 25-32mpg I have always had on the car, nor did it ever smell of excess gas.  Also, would the plugs on this vehicle be platinum plugs, if so, is there any reason to replace them before 100,000mi?  Thank You, Julie.

Answer
Sorry youre having all these problems but did they say it the presure regulator or an injector or an oring that is leaking the regulator is what controlls the fuel to all the injectors so i neeed to know if it is an injector porblem ok sorry for your problem