I am getting a random SES light with a code 44. I guess it means "O2 sensor reading lean". My fuel economy has gone from 20 mpg to about 12.5.
I don't seem to have any exhaust leaks either. I do have SLP shortie headers and single wire O2's, but I have had the headers on for a few months. This problem has started in the last week or so.
I am guessing that the at least one of the O2's are bad and reading too lean, and the PCM is adding fuel to compensate and causing the poor fuel economy.

Am I on the right track? New O2's for my car are pretty cheap, so I guess I might as well replace them.

 

I replaced both O2's. (passenger side was a biatch with my SLP headers) Here is a pic of both old sensors. The drivers side was pretty sooty, while the passenger side looked a little better.

 

Definitly looks like it may have been the problem. Which side was the code referring to (bank 1 or 2)? If the code was referring to the side that was all covered in carbon then it would seem, to me anyway, that it would have been the issue.

The real test is, did it fix your problem? Seeing as how you already changed them.

On a side note, our 93's have a history of running into problems with longtube headers. Since our oxygen sensors are not heated (hence the single wire and cheap price), the sensor does not get hot enough to perform correctly because it is so far down stream of the exhaust. That being said, I have longtubes on my car and I haven't noticed any ill effects of this.

You should come over to speeddensity.org.

 

My car runs 100% better. Fuel economy is back where it should be. It idles smoother, feels stronger at part throttle, etc. I don't think the 93 codes specify which bank the code comes from. All I found was code 44 is lean, and code 45 is rich.
I do browse the speed density site once in a while. I need to read more over there.