azurite300e

Just today I finished installing the O2 sensor. Bought a brand new in the box Bosch 13942 (for Ford Mustang 5.0 V8) off ebay for $35. Just spliced the wires from the old sensor and now it easily plugs right in. As a matter of fact the sensor was cut-off and removed many years ago before I purchased this car. We used to only have leaded fuel in this country which quickly damaged those sensors, but now for a couple of years we also have unleaded premium 95 octane, so that is why I decided to reinstall the o2 sensor.

I measured the sensor output voltage while it is hooked up to the CIS-E and apparently it still seems to be sensing a rich mixture. It reads about 0.84V after I let it warm up 2-3 minutes, although I'm not sure this reading by itself means there is a problem. I still have to replace the "Check Engine" light bulb in the instrument panel to see if it hopefully stays off, as that would be a good sign. The bulb was removed a long time ago also by the previous owner who probably got annoyed because it stayed on all the time after the sensor was removed.

In case the Check Engine still happens to come on, what do I also need to check next to possibly remedy a overly rich mixture problem? The car was running pretty well without the sensor, but I'm getting only about 150-160 miles out of a full tank. And of course there are black sooth deposits in the tailpipes, and some on the spark plugs when I clean them every 6 months or so.

Thanks.
-Alex