This started about a week ago. Upon the car's first startup of the day, There's this dentist's drill kind of sound coming from the engine. It goes away once the cars is warmed up, but it has never done this before but has everyday for roughly a week now.

any thoughts?

Secondary Air injection Pump.....

Thing is crapping out.......runs for a couple of minutes on cold start to warm up the CAT

hmmm, is it a necessary fix (as in, is it harmful to leave alone?)? Is it an easy fix? I really have no clue where or what it is aside from what you just mentioned. I have no problem doing the work myself though.

Me too I got the same problem going on with my car, but I don’t know if I should replace the pump or not. Is it necessary?

It's there to help the cat hit optimal temperature faster for emissions reasons. If it's not working you will produce more emissions each time you start the car, because the cat won't be working properly for a longer period of time. It's nothing to be overly alarmed about. If it fails totally you should get a CEL.

yes it's not a must just helps...I believe alot of the FI guys disable this all together!