The bad ground issue seems to continue to come up in my efforts to resolve this. It seems to make sense, as the http://www.continentalimports.com/ser_ic40142.html article states the pushbutton module is logically pogrammed to show an unrealistic value is an open circuit in the sensor or a short to ground is detected. Other than the A/C, the car seems to be fine. I have not driven as much as I normally would, but it doesn't seem to running bad.