Do I need to keep the oxygen sensor that is in the bottom of the manifold, where the exhaust pipes exit? What will happen if I just unplug it?

thanks

 

Are you still running the factory computer controls? If so removing it is probably the worst possible thing you could do as the O2 sensor is one of the highest priority sensors in the system. The car will run horrible!

Removed the computer controls? Then the O2 is no longer needed. Disconnecting it will not harm a thing. However, remember, it does provide an obstruction in the exhaust. You could remove it completely and replace it with a pipe plug from your local hardware store.

 

Don't remove the O2 unless you're going to a carb. The computer needs the O2 readings to adjust injector pulse width so the car will stay close to stoich (14.7:1 AFR). If it doesn't get any readings from this sensor it will default to a table that is similar to the start up table and run the car quite a bit richer that it should be.