Hi I have just got a LPG RX300 SE 89000 miles my lights are on went to Lexus today was told by a very nice bloke that used to fit LPGs to cars that it's because the gas as a lot of water in the gas and to change the sensor will cost £250 but he did say it may only last 2months so he said it you can live with the lights on it's ok. Now he also said your gas conversion will only last about 75000miles on till you will need to get the head done valve seats need doing at a cost of about £750 up wards . But he did say it's worth it but it can only be done once . Then it's a new head .hope this helps Ray