On stock tuning, the LPG injectors will mirror exactly what the gasoline injectors are supposed to do, with a slight correction factor put in so that your stock O2 sensors will be happy... but it's your stock ECU that controls closed-loop tuning and the preset ECU maps that control fuel... the SGI computer just translates those instructions for the LPG injectors.

Thus, it's really important that your LPG AFRs (air-fuel ratio) closely mirror your gasoline AFRs in closed-loop (typically 0-3000 rpm on a modern engine) so as not to cause weird running due to your stock ECU trying to adapt to the LPG.

But the cold running issues can be due to tuning and/or vaporizer/coil mismatch issues. We're still discussion ways to figure out how to regulate fuel pressure when it's cold... apparently, changing the fuel pressure setting on the LPG vaporizer helps for some people... we're looking at the problem.