INCREDIBLY annoying chirping sound

[DieselHead]

Hi everyone,
Yesterday I replaced one of the three rubber air filter housing mounts, and relocated my boost gauge from near the right knee of the driver, to above the left air vent, next to the instrument cluster. This morning when I pulled the car out to drive it, I heard this really pretty loud chirping sound coming from somewhere in the engine bay. I can't decide where, somewhere around the passenger side, possibly near the air filter or near the belts. I drove for about 80 miles and noticed no change when I came back home.

There used to be a sound of loose marbles coming from the air filter, but that has gone away probably because of the housing mount replacement.

Also, when I tap the throttle, not hard, if I touch it at all, the chirping goes away. I really have no idea what this could be and it didn't really affect the driveability of the car. I fixed that filter housing mount because I was looking forward to a nice normal sounding idle, and now this. Are there any typical causes of this? Slipping belt? I applied some belt dressing which didn't seem to do anything. Thanks for the help

Alex