What is the power drive button used for and how do you fix the the fule gauge?

the power utton changes the shift points of the transmission so that when the power light is on it takes alot less acceleration to downshift the vehicle, resulting in higher rpms which means more power. instead of accelerating and the vehicle staying in the same gear through more accelerator depressment. Answer to part 2 of your question... http://wiki.answers.com/Q/Why_did_your_gas_gauge_stop_working