My belt always used to squeal on my 03 protege. Normally when I start up but other random times as well. Now there is a loud solid smacking noise whenever it's running consistent with my idle and squeal stopped. I noticed there's a spot where the timing belt covers rubbing on the water pump a little and the belt to the alternator has a little more play than the other one but other than that, everything looks fine. Anyone have any ideas or is there something else to check.

 

Also I can feel the vibration if I put my hand on the valve cover

 

A couple of suggestions : Look at the pulleys when the engine is running and see if they're turning smoothly and not loose. After that, check the tensioner on the timing belt.