Ford Repair: Front wheel drive Ford ContourTransmission, catalystic converter, ford contour

Question
This problem is for a Ford Contour XL 1998, V6 2.5 LTR,DOHC, Automatic. When driving at low speed or taking off from a red light at a green the transmission bumps the entire car?

The Check Engine light is on, but when I did diagnostics on that and tried to clear the code (P034) several times. It just always kept coming back on. This code when looked up indicated that the left bank at the catalystic converter was not receiving enough oxygen.

Also I has not changed the personal filter that is closest to the passenger side since I purchased the car in 2001.

Not sure if any of these other items are associated with the transmission shifting problem?

Any idea what it would cost to fix at the dealer level?

Thanks for your support.....

Keith

Answer
Hello and thanks for the question...I'll try to help.
Since you haven't mentioned any other shifting problems, I'm not sure that it's your transmission that is causing the "bump". It sounds more like a broken transmission or engine mount.  I would have a garage take a look at it.
Erik