ok guys you had it right!! Hallalujah! the story starts when i replaced an o2 sensor about 2 yrs ago. just bought the vehicle new y pipe first off, followed by said 02 sensor. fast forward til rcently when the CEL showed an 044 code "lean o2 sensor". i assumed it was working fine since it was "recently". replaced. tuner pro was showing very low volt readings but again i assumed it was working as it should. two days ago i unplugged the 02 to see what happened. nothing just steady .442 to .474 volts back and forth, instead of plugging it back in i grabbed a new one (thanks to jim_in_dorris!!!) and threw it in, got tuner pro up while in the lot, then my laptop basically went on the fritz but from the glance at the idc i thought the new 02 didnt make a difference, and posted those results last night. then today with fresh charge on laptop i had great readings from the 02. .800-.100s back and forth. fuel trim up and down a little, back and forth just as it all should!!!! Anyway i couldnt be happier!! thanks so much. i just want my half-way decent milage back!!! thanks again Jim and Lionel and Billy. you guys were hovering it around the 02 sensor the whole time. case closed!!!