Ramp and movement physics help

I have a infinite runner style game and I modified my gravity to around -32 because that gives me the right ramp and jumping that I am looking for. But as the game progresses the character speed moves faster up until x10 the original speed. That makes the jumping and ramps air time way to long and the character goes too high and is in the air for two long. Should I be multiplying the gravity with the same multiplier as my player speed to counteract it or does anyone know of a better alternative?

Movement script