[Solved] Mazda 6 2.0 Petrol + LPG: Engine Jerking at 2000 RPM, Throttle & Flow Meter Cleaned, Tested

Hello,
I have a problem with the above-mentioned car. 2.0 petrol + gas engine, 6-speed gearbox version. The problem occurs when driving at about 2000 revolutions, you can feel the jerking of the engine on the steering wheel and in the seat. This is quite annoying. There is no problem at higher revs. Throttle, cleaned, also tested on another and the same, flow meter, cleaned and replaced, candles replaced. The problem occurs on gas and petrol, even more so on petrol. What could be the reason? I would also like to add that when I start the car and the engine idles, you can hear it every now and then when it is choking. Maybe something has to do with the other? Please help.

And any diagnostics? Is it only replacement for a stick?

After connecting to the computer, nothing shows completely, everything is normal, checked by two mechanics. And replaced, preventively cleaned, to exclude.

In this engine, valve clearances are regulated by replacing glasses of the correct thickness.
Maybe it's worth checking if your valves are not supported.

The problem turned out to be unsealing at the negative pressure.