I got my timing belt service today......after that...they forgot to put one of the rubber washers on one of the screws on the valve cover...so i went back....and now....my car makes a high pitched sound whenever im revving up the engine....just wondering if that's normal....

 

Mine did that right after I got the belt changed out as well. I took it back and they looked at it again, and could find nothing wrong. After the pulled the valve cover and put it back on the noise pretty much went away. I still notice it every now and then but its not nearly as bad as it was. I dunno, if you do find out what it is let me know.