LPG Autogas is a cleaner burning fuel compared to Petrol or Diesel , retaining an octane level above 100 . Compared to an octane level of 91 found in standard unleaded fuel . Also cars on Autogas generally run smoother and idle better than those running on Petrol . Resulting in less residue deposited in the engine . Which translates to less wear and tear on the engine , especially in cold start up and regular running , amounting to a potential savings on maintenance .