engine noise and vibration

I have 130k on my 97 sonata and have not had any real problems.  I just had timing belt replaced for the 2nd time.  Now I have a vibration and sounds like an airplane on acceleration.  I took it back to the shop and they said the tensioner has some play.  would this cause vibration?  I don't know why they didn't say anything about tensioner before they put it together but they did mention it when i picked it up.  They are replacing the tensioner with no labor charge, just parts, as it should be.