Why does the site crash from google search results?

Question

Google

Usually the site hangs on the 4th page (by the key query) for some reason it disappears from the search results at all, only when the domain is requested ... page, disappeared again in the evening.

Answer 1

As you were told above (dimonchik2013), a single query selection is not an indicator.
It is necessary to look at a pool of requests.
By the frequency of checking positions: " appeared last night, on page 4 as usual, in the morning appeared on page 3, disappeared again in the evening ." If you check positions like this (2-3 times a day, then in a week you will start drinking carvalol, and later you will lose sleep altogether.
If you want to analyze the positions of the site in order to identify patterns, you need to:

1. select 100-300 requests for tracking;
   
2. check positions once a day for 1 month (any service that displays data in the form of a table)
   

As a result, you will collect enough data for analysis, on the basis of which it will be possible to draw some conclusions.

Answer 2

one request - about nothing
Google constantly rotates the issue