lpg conversion 2.2 16v frontera fault

[scethrog]

car starts and idles+revs on petrol, lpg clicks in at 2.400
revs apprx and this also idles+ revs at standstill,as soon as engine is put under load it misfires,as if going on too three cylindrers get too 3 thou revs and it clears.only if no load on engine, new coil and leads fitted and all unions
and pipes seem to be secure,itwo others have told me
there's run bad in the cold weather??,runs fine on petrol but i do get a blow back / popping from the carb on occasion, any ideas, yours, confused of brecon

[Brooksy]

I did over 100,000 miles in a Vauxhall converted to LPG and had no problems whatsover. This was back in the 80`s when we still used to have proper winters & it always started straight away on gas no matter how cold a morning. The symptoms you describe suggest the air to gas mixture is too lean. As I recall the mixture is not adjusted at the carb as this would upset the petrol running. There was a heat exchanger plumbed into the heater pipes and this had an adjustment screw for the gas.