i'm not sure but i think the EGR valve is the butterfly just behind your throttle body, but thats a guess..
If your harmonic balancer is bad it wont throw off your timing since that is run off a magnet mounted to the center not the outside, but your accessories and supercharger wont turn proper.
Changing the crank sensor req's pulling the harmonic balancer off so...If it looks like its dry rotted or can see stress marks in the rubber its $100ish part to replace which is less than the labor will prolly be if you have a shop do it.
