There are 5 burners. Between the two on the left there is an electric igniter, and between the right two there is the heat sensing element. My problem is that only the two burners on the left get lit, but the other three don't and this causes error codes 14, 34, since there is no flame at the sensor.
This used to work fine after a couple of tries, but finally stopped working. I have to cut power to the furnace, and sometimes it works and sometimes it doesn't after that. If I slightly blow diagonally from the left to the right the flame propagates - meaning there is enough gas, because I'm not fanning the gas but the flame. I used a bottle cleaner brish to get rid of some spider webs and dust, but still same thing.
I guess I should take out the burner assembly and give it a good cleaning?

Remove burners and clean burner flame jumper areas. Then check for the proper gas pressure with a manometer and adjust to the factory recommended setting.