Okay, I am hoping this will get more attention here..

I am really needing some help with my 1993 Grand Prix LE.. it has the 3.1L MFI engine.

My problems, that I know of, are as follows:
High idling temp, though it goes down. (Gets to almost 240.. I'm thinking water pump maybe..?)
There is a coolant leak right under the t-stat housing. Can anyone please tell me what might be leaking?
I think my belt tensioner is bad. It wobbles when running, not just the pulley but the whole arm.
My car will periodically stall and/or hesitate like crazy when accelerating from an idle.
My car will periodically stall when turning from an idle.

Any help would really be appreciated..

Edit: Also, forgot, I usually average 12mpg...