95 Mystic TA

After a bad ruff ideling problem, I had the car scanned and the passenger side O2 sensor was to found to be at fault. It was hanging lose and had been for about 2 years since the headers went on because I never had it tapped in. It ran fine until now. For the time being I just unplugged the sensor. How should the car be acting? Should I be running rich? So far it idles and drives fine but a knowledgable source told me it shouldn't be running right at far as the A/F ration goes.
So what are my choices?
-Get a fitting for the O2's welded in?
-O2 simms?
-Any problems arive from getting Brian at PCMForless to write me
up a program and just remove that O2 sensor? Thanks for the advice in advance.

Injuneer

You say one of the O2 sensors has been hanging loose for two years..... what about the other one? Why would you tap in one and not the other? Didn't the SES light come on? Should have.

You can't delete the pre-cat O2 sensors, not in ODB-I or in OBD-II unless you make a concious decision to run the engine in open loop at all times. That will prevent it from ever correcting to any changes you make. And you can't use "sims" in the pre-cat position.... they are only for the after-cat positions in the 4 sensor OBD-II (96/97) cars.

It will run "OK", but it isn't going to make the corrections required to keep the engine operating at 14.7:1 A/F ratio. If you run a little richer, you will get poor fuel mileage, and possibly foul the plugs. If you run a little lean, you could get excessive knock retard.

The "closed loop" feature provided by the O2 sensors is what makes these engine fairly fuel efficient, allows extended plug life, allows the PCM to repsond to changes like improved inlet air and improved exhaust.

95 Mystic TA

Thanks for the reply Fred.
The driver's side had a fitting already so it has been "plugged" in. The SES light comes on occasionaly but a scanner reported the there was low voltage going to the MAF sensor.

Thanks for the advice, off to the exhaust shop to get a bung welded.