I have an autometer a/f gauge and an apex turbo timer reading voltage on the o2 sensor. Sometimes the a/f gauge works right, and the tt shows the voltage fluctuating between 0 and 1 volt. But most of the time, usually after some driving, the a/f gauge stops working correctly, and the tt starts reading between approximately .5 to 1.4 volts. What would cause this, I've been through 2 o2 sensors now (both were used though) but I find it odd that both would do this. Are there any other sensors that could go bad and cause this?

I have a 92 civic dx w/97 LS motor with 95 LS ecu.
Drag 3 turbo kit, with walboro 255 lph fuel pump and vortech fmu as my fuel management.

Any help is greatly appreciated.

Also, I have no catalytic converter, just a cheap flexpipe that I got from autozone.

 

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