Thanks everybody for the replies. Looks like the first thing I need to do is what my gut feeling said - fix the exhaust 1st. Gears - I'm not sure how to look up the codes to find the gear ratio. Engine size - the sticker is wiped clean. No information is legible. I just assumed it was the 5.3 by the severe lack of power. As for my driving habits - I'm getting 13-14 MPG's..... I drive pretty dang conservative, lol. I would hate to see it if I were heavy footed!