maybe your. my car ran 14.55 my first time out with nothing but a shifter and H-pipe and crappy stock 2.73 gears. Myabe there are alot of bad tracks and bad drivers around you? high elevation? you only go to the track with 80* and 90% humidity?
last year a guy at the track had an 01 gt kicked my butt, still have the slip, and ran a 13.7@100. Talking to him in the pits he had zero mods so I pulled his air silencer for him.