what have you been getting lately? like 22 or 23? cuz that could just be the winter gas like stated before, but some damn sensor is probably on its way out, definitely try to get a scantool, or visit your local autozone!

on a side note, do you think having a code 41 cam sensor/magnet could make my mileage drop from 18-19 to 14-16?

i get about 25 as an avg in the summer yeah, but umm...i didn't get this kinda mileage LAST winter..EXPLAIN THAT.

I am just going to leave this whole gas issue alone for a while until if figure out my new transmission woe.

Get that o2 man, it'll take care of more problems than you think.