95 G20 02 voltage??? Help!

[lowpass5]

Hi,I'm new to this forum. I have a 95 G20 that won't pass emissions. I was wondering if any of you know the correct O2 sensor voltage for this car. I am reading 0.94 volts fluctuating some, but not significantly. I was expecting something around 0.45 volts. I notice that I get about 0.3V bias with key on engine off. The sensor responds quickly to induced vacuum leaks but returns to around 0.9 even in the presence of a leak. I checked the engine temperature sensor to make sure the computer has the signal to go into close loop - it is working fine. It acts to me like it's not using the O2 to control the mixture, but the vacuum leak response puzzles me. When I pull the hose, the reading drops to around 0.2V, the recovers to around 0.9 and stabilzes. It's less than the 0.94 without the leak, but it seems to be responding. Does this seem correct?

The car is not posting any codes. i have had it to 2 repair shops without any results ( but with significant cost). Any advise of a non-suicidal nature would be greatly appreciated.

[RED_DET]

.94 volts seems reasonable. Some that due minor tuning on turbo cars use o2 voltage for reference. Anywhere from .92-.94 is ideal, anything from .95-1.00 is rich.

[FrontierMan63]

Hi, check 2 C if the Voltage switches high-low when U rev it @ about 2000 RPM's? A volt meter w/Max-Min readings (Fluke 88) will tell U if it is switching Rich-Lean, That would B Normal. I'm guessing we R talking about The Front O2 (OBD2) ? i cant remember on 95's! Also Ck 2 C that U have 5volt ref. volts, & good ground @ sensor. I hope U already have it Fixed? Good Luck,Rich

[lowpass5]

That's what it's not doing. When I hold the Revs at ~2000 I get a steady 0.94V or so. I can get it to lean out if I ubruptly step off the gas, but it returns to 0.94V. Same is true for the dash blink test. For some reason, it is not trying to control the mixture with 02 sensor. The sensor is new, and seams to respond quickly to induced vacuum leaks. Just not going into closed loop.