Actually I didn't run carfax until after I sold it. I had problems with it since day 1 and my father and I always suspected that it had been in an accident. I had a free carfax for some reason so I checked it just out of curiosity....sure enough it had been totalled and salvaged. ALWAYS check Carfax before you buy...even if it misses a lot of accidents it's well worth the $20.
Just consider yourself lucky that you haven't really had any problems with your car.