My wifes 04 SXT has developed a thumping sound that increases with speed. It sounds like its coming from the left front. I have rotated the tires checked pressure and changed the breaks(they needed to be done anyway)and seams to improve after being jacked up but eventualy comes back. When I drive it, I feel a wobble in the seat mostly between 25 and 30 MPH. I hate taking a car to the dealer with out some clue what could be wrong, thats how they soak you. Does anyone have any thoughts for me to check.