what's wrong with my car?

So, my 91 accord's got this thing called 'sports mode' that seems to have a mind of its own. It turns on by itself either when i start up my car or even when i'm driving on the freeway all of a sudden. what's freaky, is that once it's on, my car doesn't shift, it just stays in 3rd gear. anyone know what's up?! i figure it can't be the transmission, cuz i can shift just fine from park to reverse. sometimes when i mess with the fuse box it turns off, but not all the time (so ... ehhh, someone help!) if anyone knows how to completely cut off this sports mode thing, then i'll be a happy camper!

There may be a short or something in the little button on the shifter.

Good chance that it's a bad TPS (Throttle Position Sensor) and needs to be replaced, check the connections and wiring for any problems first.