Sounds like google dance to me. I wouldn't worry as long as it comes back
I have sites that loose-ranking only to have them come back a few weeks later. Anyone have ideas regarding this?
Well its happening to my website also. Many of my keywords were appearing in 1st and 2nd page of Google and suddenly after few days it dropped to 4th page. Surprisingly one of my cricket related blog was ranked in 1st page of MSN for 9 separate keywords. Next days all keywords dropped to 2nd & 3rd page. Google page rank of website has been steady as rock for last two months. Awaiting for next update of Google PR.