whistling noise from under the hood-when s.e.s light is on
 

i know i need to get it hooked up to a code scanner to get to the bottom of this, but ive got a weird issue with a check engine light that comes and goes, and when its on theres a loud whistling sound from under the hood, cant seem to tell where its coming from, almost seems like it could be a vaccum leak of some sort. tried tapping on the e.g.r. to see if that would help ( dad has had egr issues in the past and sometimes giving it a few good taps would unstick something, that was on the '94 however, this engine is entirely differnt) didnt know if anyone has had a similar issue. has no running or driveabilty issues, just a annoying sound that only seems to be there when the s.e.s light is on.

well first thing id do is spray some carb cleaner around the intake and TB. if the vacuum sucks in the cleaner the rpm will fluctuate.