Are you sure its a valve noise??? My '92 'yota with the 2.4 liter 22re engine started making noise.. the mechanic thought it was rocker arms at first.. here it was the timing chain.. and thats a pricey fix.. the 6 cylinder's cost less to change the timing belt than the 4 cylinders chain.. I would check your timing chain and see how loose it is. if u do replace it, don't skimp out.. replace everything because if you don't it will start acting up again. if you have any other questions, drop me a message.. add me to your IM if you like.. no_cool_user_names_left@yahoo.com