Ok so yesterday was the day that I had enough of Check Engine light bullshit, so I took both fuel senders out and find that there is a fuel line that connects both of them. That line was trapped below one of the fuel level sensors blocking it to drop all the way down. After I untangled them and assembled everything back it works perfectly. No Check Engine light, no wrong readings in the fuel gauge.
For information how to take fuel senders out I used this YouTube video (there is actually two senders, one under each back seat, the removing process is the same as in video)
The guy in video shows how to remove fuel pump, you don't need to do it, just to take all that white thing out and check if nothing is trapped under / above fuel level sensor:
[ame]https://www.youtube.com/watch?v=ELq72XVlJrY[/ame]
PRO TIP: If you will try this method, make sure you are almost empty on fuel, because there is 99% chance that it will spill out when you will try to remove the fuel sender from fuel tank.
How those two senders looks like and how they are connected:
https://pasteboard.co/HvaTiug.png