How is the lpg delivered? Through the throttle body? I would say maybe you have a problem with a regulator problem or it also sounds like the timing isn't advancing. I don't have much experience with obd I ( is that what computer you have)
7" long arm lift, HNT sye , herculined inside, bush wacker fender flares now geared and locked !!!
62 mm bored throttle body's fs - pm