I feel your pain. I've had that too and I am on HostGator as well. Personally, I think it may be a plug-in causing the issue, but I haven't been able to pinpoint anything. One thing that I did that you may want to consider is to keep track with a traffic report. I use the traffic report feature from WebCEO. I get a weekly email about my site speed. Not sure what I did to change it, but my rating has improved in the last few weeks. Good luck!