l own a 2004 fiat petra with registered lpg fittings.Some time back when l use to fill gas around 40ltrs and petrol of around rs500 l use to run around 425kms.But now l am getting onlt around 330 to 350 kms.Please help why.

Replace the 'diaphragm' in the gas kit when you get it serviced and meanwhile take a soap solution and apply on tube joints to make sure there are no leakages. l think your problem will be solved.Every month, under the gas kit there is a button screw, which if you open will drain out the dirty water, this also helps in mileage.