Forum Moderators: open
?
In case your changes did have an impact (Have you checked whether the new version of your pages is already in the google cache? If not: It is unlikely that the change in ranking is caused by your change in template), changes in the link-structure or keyword-density might be the cause.
You have not switched to frames?
Remember the home page PR is made up of the incoming links from off-site and on-site links.
These days looking at the cache is not enough as it's way off with PR updates.
Should also consider PR recalibration, which would have take place with PR updates. Though a drop from 5 to 3 seams severe, its possible.
You should aldo consider any external links deep linking to your old pages.
Anyway: I experienced that a drop in PageRank did NOT harm the ranking position for my keywords. So do not bother too much about a drop in RageRank shown, as long as your position in the SERPS remains the same.