High pitched noise on start?
 

Ever since i bought my 2005 blazer, when ever i push the gas i get a high pitched noise over top of the normal engien rev and intake noise. I cant seem to tell where its coming from or what it is. Also when i let off the gas, it seems to keep the rpms up for a couple of seconds before going back to normal. Now once im going after that it all goes fine, its just when i first hit the gas.