I had sensor go intermittant - problem was bad solder connection where wires connect to micro switch - easy fix and much much cheaper than new sensor - so remember this
Recently, I posted here regarding an issue I have been experiencing with my '02 996 TT. Specifically, it "pops" out of second gear while de-accelerating unless I keep light pressure on the gearshift with my hand. Now, I may have a problem getting it fixed.