I have a 00 GT. It has Bassani X-pipe with cats. I keep geting a trouble code that the heated 02 sensor is lean. When the car is on the scanner the passenger side upstream sensor reads 0, but the heater is showing that it is working. I put in a new Bosch OEM style 02 sensor and still the same thing. The car also seems to surge when the A/C is on while driving at a steady pace. aNY SUGESTIONS?