Single Post Loading Very Slow

Hi, my main page http://www.symphonyoflove.net/blog and the categories page are loading fast. But my single posts are talking as long as a minute to load. I have upgraded my wordpress to 3.1.3 and still having this problem. I have deactivated all plugins except the spam control and I still have the same problem.

It was working fine until about a week ago when I added mailchimp.com sign up form. However, that should not be the problem also as I have the same sign up form working in another blog using the same theme http://lovequotes.symphonyoflove.net.

I have looked through all the codes and basically I did not make any changes except adding the mailchimp code to my sidebar.

I have also tried to Google for solution but couldn’t find any.

Any kind soul please advice what else I can look into or how can I solve this. Thank you.