[Mohycle]

Thanks Crewzin,
I disconnected the negative for a couple hours, and also disconnected the sensor. Reconnected the sensor, reconnected the battery, now after a half tank, seems to be back to 25 mpg or so. I may have exaggerated the initial mpg drop; pilot error. My tank was not topped off before. But there definitely was a drop, which now is better.

Thanks again. These cars are a little high maintenance, and the info on this site has saved me lots of time, trouble, and money.

Mo