bad o2 sensor?

[99Mitsu]

My car is running REAL rich. My bumper is black within a half hour of cleaning the soot off and I'm getting HORRIBLE gas milage. I do not have a logger or OBD II reader is I cant go at this internally. I have a downpipe for my exhaust so my catalytic is not there. I ordered a new o2 sensor (the one by my turbo) and I was wondering how can I tell if my sensor is bad when I take the old one out?

thank you
~mitsu

 

[viperlp01]

turn your car on and get a multimeter... Tap into the BLUE wire in the front o2 harness see what the voltage reads.. It should be around .5 volts...