Oldsmobile/Buick Repair: electrical & front end, hi tc, buick century

Question
I have a shimmy in my 96 buick century up around 65-70. I bought it used, and the car lot put new tires on it and  had the wheels speed balanced. it was ok for awhile, but came back. I had it checked and no one seems to be able to pinpoint the problem. I have heard of this problem from other buick/olds owners, but no one has an answer. any ideas? also, how do you reset the "service engine soon" light?
                     thanks for any help you can give.    T.C.

Answer
Hi TC,
The light requires a scan tool to erase any codes, and they should be read and addressed first.
Any chance the shimmy is engine related?
To find out, you can get it up to the speed where it shimmys, and shift to neutral, and let off the gas.

Bent wheels can cause the shimmy also, and some of them don't take much to bend.

Van