I have read in other I30 forums that some people experience a shimmy/shudder/vibration while driving their car. I stumbled upon this software link which supposedly helps in narrowing down the source of automotive vibrations. Just tryin to be a good forum member

http://www.vibratesoftware.com/

 

My experience (automatic tranny) provided that under light acceleration, a vibration occurred (more like a thud) most significantly shifting from 2nd-3rd. The TPS needed to be adjusted and it was an easy dealer fix.