Sorry for my bad technical English. I have an old Audi 100 car, dual fueled LPG + benzine. I have problems with the "gas minimum" (dunno the english term: I mean the gas rate which enters the engine when the accelerator is fully up). The benzine minimum is really too low for the car to stay on: I will eventually find the screw and raise it. The LPG minimum is UNSTABLE: sometimes it is pretty high like 1100 rpm, sometimes it is too low like 800 rpm and the engine cannot stay on easily.
So the question is this: what is the "broken" part when the minimum isn't constant?
Thanks in advance