originally i was on page 30 then i disapeared and was nowhere to be found for a certain key word,..then after numerous SEO updates i was showing up on page 4 of google search results. i stayed there for few weeks without making any changes, today i look and i am on page 22.
why am i fluctuating from page 4 to 22 and so on?

thank you

google is constantly trying different filters in their algorithm and you may have some links or procedures that are being tested to see the impact on sites they consider authority