While searching you are not getting results for a particular site or list

Scenario:
Access is denied. Check that the Default Content Access Account has access to this content, or add a crawl rule to crawl this content. (The item was deleted because it was either not found or the crawler was denied access to it.)

Solution:
Access Denied , that means its clearly a Permission Issue.

Few things to try :
1. Check for the Site Collection > Site Settings > Search Visibility > Make sure its set to Yes
2. Check for the List Settings > Advanced Options > Search option should be Yes
3. Make sure Default Content Access account have access to the site. You can check it by logging to the site using that account.
4. Create a new crawl rule for the site with a different account which can access the site.