Lately one of my websites have been jumping all over the place for major targeted keywords. One day it is on page 2, the next day it is on page 11, then five hours later it is on page 4.. The site has only been up for a month and a half so it is kind of new.
oh new sites get google dance , but this affect is happening with my 2 and half year old site , i dunno wats wrong with google going on
jump up and down happen commonly especially for new site However, recently google panda update also affect the serp as well
Don't worry about this as your website is new. It usually happens to new sites and sometimes is called as Google Dance. You need to add more content and/or links to make it stable on the top, otherwise it could jump up and down longer
Have you checked Serp with Goggle accounts closed (gmail or G+ signed out) ? Google modifies Serp according to the opened Google account and it's browsing history.
david_deseine is right. You are seeing so vast difference in ranking because it may be sometimes you are logged in (gmail) and sometimes logged out. Google show different results when logged in and logged out. You must always make a google query only when you are sign out. This will give you true rankings.
Many factors but definitely, SERP algorithm updates usually makes this result fluctuations. All you can do is make your site indexed more often with good content update and good new backlinks.
It takes awhile for Google to place you in your correct initial ranking but what's important during this phase is that you do some backlinking and progressive backlinking that looks natural. This'll heighten your chances for a higher default ranking and in the long run, make it easier for you to climb up from wherever you start.
New sites do tend to be the victim of Google Dance. So the fluctuations are expected. The time to worry is when this fluctuation continues.