my o2 sensor has major black stuff on its tip and its only 4 weeks old. 89 2.8 camaro what is this and has it gone bad? code 44 has appeared 4 me should i change it or is it normal?

 

What did the old one look like? Were you getting the code before replacing it?

 

it looked burned out. how can i tell its bad and how can i test it?

 

to test it un plug it, then start your car, then get a volt meter and put the positive lead on the wire coming from the sensor, and ground the negative lead.the reading should be jumping around a little bit with an average of .5 volts.

 

aure you running really rich or burning excessive oil? Sounds like carbon buildup.

The only accurate way to test a o2 is with a scanner. You should have crosscounts from about 200mv to 800mv, with the center around 450mv (stoich).

Once the o2 is reached 600deg, you can get an accurate voltage with a DMM, but it's not going to have a fast enough refresh rate to give the crosscounts.

YOu can get the "battery" effect going on the old one by sticking it in a vice and heating it with a torch to 600 deg, but I don't think that will give the x-counts either, just an average voltage reading.