Agree, could be the timing marks that don't line-up, but not sure that would really cause vibration..it would make the engine run rough and misfire. Did the CEL come-on? Did you double check the drive belts? Are they to tight or to loose? That could could vibration sensation. I assume you put engine at TDC when your removed the TB. Did you put a new timing belt on or did you use the old one again? if the latter, did you install the belt in the same 'direction' as it came off? The belt stretches in the 'running direction'. If the belt is now running in the "other direction", could possibly be causing vibration as well (and you would run the risk of premature belt failure). Here are a set-of instructions on how to take the timing belt off and how to install it. You could also search the site, as Bruce2 suggested and find pics and procedure. Also, go to kiatechinfo.com and get the instructions from there.