What should by O2 sensor voltage be? Do I check it when its completely warm? Search isn't working for some reason, it keeps giving me some database error page.

Thanks,
Rob

 

Basically, the car should be warm, but the sensor has a heater and warms up pretty quickly. They are calibrated for 14.9:1 air to fuel ratio. At the perfect ratio, you will have 0.5v. However, the voltage changes quickly to .2v indicating that the fuel system should add more fuel and higher to .8v to indicate too much fuel. As the sensor gets old, the voltage drops and the ECU thinks you need more fuel. This happens over time is will cause a 20%-50% drop in mileage. My 93 Si made 14 mpg until I replaced it (240K miles), now I am back up to 23. FYI: Factor rated 21 city/ 24 hwy for 93.

I think that 92 is extremely close in mileage specs.