SpList add item System.web.HttpException

Hi

I am having an ASP.Net web application deployed on Sharepoint 2010. We are facing slowness issues with the site. To Find out the reason we have created 1 list which is not related to the application, most of the times it is working fine. But today I got a System.Web.HttpException: request Timed out exception while entering a value in the list using OOB interface.

There is no other log present for the same co-relation Id. Any pointers, where should I investigate?