The hanging in revs is 'throttle hang' for emissions reasons.
As for the 'noise,' could be a chain rattling, but that doesn't seem to be too common with these cars. Does it only happen when starting off in 1st? Does it do it at idle? First start up?
it makes when you first start off in first only at low rpm's.. and in second at low rpm's.. no noise on start up.. and you can hear just a lil rattle when its idling with the hood up...