I have a blog on Blogger.com (coratcoretblog.blogspot.com) and already has PR 2. Is if I buy a domain and change the domain name on my blog at Blogger.com (custom domain) will reduce my pagerank?
If you do a 301 redirect then i think that you can retain your PR.. I am not 100% sure so better wait for someone who is sure
Because of changes at google this is all in the wind. Since the last PR info was given the answer would be yes. Because but doesn't mean you will lose it all. If all the other links to your blogger.com was updated to the YOURDOMAIN.com then you will more then likely keep it. As well as the 301 mentioned above would help as well. But remember its really comes down to the links to YOURDOMAIN.com. I personally wouldn't do the 301 becusae from my experience haven't had it help moving PR's. As what some people do posting a status page that says the new update it YOURDOMAIN and having a link to the new site as wellas possible an auto redirect would be more helpful for you. But can not stress this enough, is that it still comes down to the links to the new domain.
So my PageRank will drop if I change into my own new domain. I've heard about 301 redirected, but it is not recommended way.