1996 Chrysler Sebring

My wifes 1998 Sebring makes this strange high pitch squealing noise. About 2 years ago, this started and only lasted a few seconds after starting it and then went away shortly thereafter. So I kind of thought of it as nothing serious - only needs to warm up, etc.

Now, this same high pitch noise is noted for a longer period of time (since the weather is cold and engine takes longer time to reach operating temperature).

The noise sounds like it is comming from the gas tank area although I can not pin point it because of the car being so low to the ground. I do have a good mechanical / electrical background (I always enjoy working on my own vehicles if I can justify my time to save myself from a substantial mechanics bill).

I would really appeciate anyones input, especially the owners of Chrysler Sebrings - seems to be unique?

Thanks, Rick