I’m still getting pages sometime ranking like 4 or 9 then after few days will disappear to not top 100?

Google usually works like this:

• If you write an article, the article is fresh and Google will index you depending of your article optimization.
• If the article is indexed and people are not reading it, not sharing it and are not sending links to it, after a few days Google will consider the article as not important and change its rank position.

This is just one possible reason why your rankings may go down. It’s important to consistently monitor the rankings of your key pages, and add them to Focus Pages if you see the ranking go down. The Focus Pages system will run a diagnosis of your page and indicate tasks you need to complete to improve that page’s chances of ranking at the top of Google Search.