Another comment on the belts, make sure all SMOOTH surfaces of pulleys are touching SMOOTH sides of belts. Ribbed pulleys touch ribbed parts of belts (pay particular attention to alternator deflection pulley)
As for your idle, you most certainly have a vacuum leak. Check CCV plumbing particularly around valve cover and the one that snakes into the manifold DIRECTLY to the CCV. GL!!
Replace all vacuum lines/seals. See third link in my sig!