04DSGB

I have an 06 GT with 71k miles and I am having a problem. When it rains my car makes a squealing noise that continues for a few days after. I replaced the belt about 100 miles ago and the noise went away for 2 days and came back. I have took the belt off and started the car and it sounded perfect. I spun all of the pullies by hand with the belt off and they all seem fine but I am thinking the tensioner might be bad. I am hearing a knocking sound at startup now after the car sits all night so could it be a bearing in the tensioner going bad? Any help is greatly appreciated.