standing at the front of my 06 sebring 2.7 is the front or back bank 1 and is the top or bottom sensor1/2 and which is considered upstream/downstream.
thaks

 

Bank #1 has cylinder #1 in it.

Cylinder #1 is the rightmost cylinder in the rear bank. Things got confused like this when they started putting engines sideways in front wheel drive cars. Before that, when engines were oriented properly, the front of the engine faced front and the #1 cylinder was on the right. Then they rotated the engine but kept the numbering the same.

Are you totally confused now?