My client had two WordPress sites that all of a sudden slowed to a crawl. We reset WordPress, deactivated plugins and spent literally hours trying to figure out why the wordpress sites were loading like a slow snail. I recommended to my clients that they move the hosting to Hostgator which we did. During the migration, Hostgator found embeded malware that we certainly did not install in either site. In fact one was an image site that nothing new but UP updates when needed for 2 years! After cleaning the affected pages and the sites are both running at lightning speed again. No change in theme, no deletion of plugins … nothing more than removed injected code! I have called Godaddy’s support team and let them know .. and if you have this problem you should look at this before you spend so many hours trying to fix it on the plugin or theme side. It literally took 5 minutes for Hostgator to fix this!
Good luck JKS