Yesterday mechanic changed my timing belt and water pump. After that the check engine light become on. When I check it the result four cylinder misfiring. In addition the engine does not work smoot. What is wrong with it:licka:

The mechanic could have gotten one of the camshafts set one tooth 'off' of the correct one - or maybe there could be a vacuum or PCV hose that has come loose or is leaking? Its hard to tell.
After you have driven it for a while -like 1/4 tank of gas- you could remove the spark plugs, and see if they are light in color and dry (as they should be) or if they are dark or black or oily looking. That could indicate a spark problem or a fuel/problem - but it still wouldnt point to a specific thing to fix.