I know that you can tune out the post cat O2 sensors, but is it possible to tune out all of the O2 sensors?
Also, if it is possible what affects would it have on the car as far as performance and MPG go.

Thanks

 

You can program it to run in open loop all the time, but you'd better know how to tune it, and there's not much chance of your mileage NOT going down. Some guys (who were) on the LT1 Edit list have done it. You can search the archives for some discussion on it.

 

Your front O2 sensors maintain the proper air/fuel ratio for part throttle driving; that's something you want for driveability and fuel mileage.

 

Yes its possible to tune out the front 02 sensors, but as stated above your car is going to run in open loop constantly and will never enter closed loop and enable PCM learning. If you do modifications to your engine or something else happens that throws everything off, then the PCM will not be able to re-adjust the A/F ratio and instead it will be locked at whatever the open loop calculation is. Long story short, your vehicle may run rich which will result in poor performance, bad MPGs, and fouled up plugs or it may run lean which will once again result in poor performance or even worse, detonation.