When I recently published and deleted a test post on this WordPress website, the post remained in the RSS feed. FeedBurner manages the RSS feed and their recommended solution for updating post changes is to ping FeedBurner. However, this wasn’t enough because although pinging FeedBurner updates changes to posts currently on a website, it doesn’t delete posts no longer on the website.
To remove my deleted post from the FeedBurner feed, I had to resynchronize the feed. To resynchronize a FeedBurner feed, go to the Troubleshootize section of your FeedBurner account, scroll down and click the Resync Now button. After resynchronizing, FeedBurner removes any deleted posts from your feed.
Although resynchronizing removes deleted posts immediately, it may take some time for websites that publish your feed to remove the deleted posts. The time it takes depends on how often they update your feed. Also, resynchronizing won’t remove the deleted posts from feed readers that downloaded the posts before you deleted them.