Well Ive been having an idling problem and well my check engine light came on yesterday and it was saying the O2 sensor is bad. Could that cause the idling problem? Ive also noticed Ive been getting bad gas mileage and a lost of performance.

 

good question i seem to be having the same problem, except my o2 sensor comes on and off whenever it appeals

 

yes o2 sensor regulates air/fuel ratio and if that is wrong these symptoms can happen, sometimes without even the cel on

 

Ya my cell is off now but its still doing the same things.

Also I only have one O2 sensor. The one on the header. I recived the car this way. Its been converted to obd1 with a P28. Do I need to hook up the second one on the cat?

 

not if you're still running that p28. It probably has the second o2 disabled, which would have no effect on your idle anyway. The second o2 monitors the cat to make sure it's working, thats it.
What was the code?

 

code 1.