Digifant 2h problem

Hello guys,

Sorry for long text.
Engine: 1.8 Digifant 2H 72KW

First problem:

I have idling problem. When the engine is cold, it is idling fine. But once it warms up, it starts bucking. I recorded a video for better image: Golf1 iddle problem - YouTube

I suspected bad o2 sensor, because if i unplug it, engine bucking almost go away (not completely, but it bucks only from time to time). Sensor is brand new. Could be it bad out of box? I replaced grounds and measured them several times and i replaced all vacuum hoses. Timing is ok, i have checked it several times.

Second problem:

Car hesitates on strong acceleration, but only at low rpms (1000-1700). If i gently accelerate, there is no hesitation. If i strong accelerate on higher rpms, no hesitation. I did tests for fuel pressure and residual pressure. They are ok according to Bentley manual. I have checked MAF sensor according to Bentley and it is ok. Throttle switches are ok. I also measured resistance on injectors ramp, where should be resistance 3.7 - 5 ohms for all 4 injectors, but i have measured 5.1. Is that a problem or it is normal?

Thanks for any advice.

PS.1: car was not driving several years and was not starting, when i bought it
PS.2: Since the car was not driving for long time, i replaced spark plugs, spark cables, distributor (also distributor cap and finger), filters and fuel pumps and cleaned injectors, knock sensor.
PS.3: english is not my natural language, so please excuse any mistakes in the text