Engine does not take cold gas???

Hello forum, my Nubira takes cold no gas on it jerks like this. When I step through the gas pedal it goes all the way. It lasts in about 300M. I have an LPG system in it, but it has nothing to do with it because on LPG the car switches only when it is quite warm driving so 4 KM. Can one help me there somehow? Thank you and greeting