Funny Noise during idle

Ok Its time to play Americas Favorite Game "Whats that Noise?" Im your Host BSapphire95GT, today we have a prime example...1995 gt 5.0 with bbk cai, shorty headers, o/r x pipe, dumped macs, aluminum driveshaft 5 speed transmission that makes a humming noise only during idling, and it goes away during higher rpms, happens while under load as well. as a side hint the idle climbs up to about 1.5k to 2k rpms and holds constant there...when driving if you put it in second gear and let off the car, it will climb in speed until you are eventually cruising at 2k.

attached is soundclip
http://www.youtube.com/watch?v=ZxHDVcDpSuk

on a sidenote...went over every single vacuum hose and wiggled it, sprayed it with soapy water, etc to determine if there was a leak, and none were found. Also when unplugging the maf the car does nothing, same with the IAC

vladasap said:

smog pump or something else on the serpentine belt
or
an upgraded fuel pump (wouldnt that be sweet?)

=)

Click to expand...

well the noise goes away when i mess with the cai...so i think its that,

my other problem is my stupid hanging idle

i replaced the iac and nothing...i dont think its the tps...or it coud be... when i unplug the maff the idles drop to about 600 and stay there. the car does nothing when i unplug the new iac...i checked the throttle stops and nothing holding it open...i even disconnected the throttle body cables...car does throw a code...tomorrow im going to use the paper clip jumper from the idle thread, a mechanic i took it to thinks its my ecu going out...how possible or probable is that?