Breathing space

I read with interest the recent letter about a VS Calais that apparently has a fuel consumption problem. I suggest a check of the earth circuits to both the oxygen sensors back to the PCM. Some VS Commodores shared the earth circuit with the heater element within the sensor and others were separate. Regardless of which, there should be continuity present, otherwise the oxygen sensors do not react rapidly. With the use of a Tech 2 scan tool, the oxygen sensor outputs and long-term and short-term fuel trims can be monitored and checked.