path 13 may contain liquid and fuel particles which would cause hego sensor 10 to crack during its rapid increase in temperature this type of thermal shock phenomena limits the capability of current oxygen sensors with high wattage heaters to enhance this capability and to combat thermal shock this invention places vaporizer 14 upstream of hego sensor 10 with key on vaporizer 14 can be turned on so that when the vehicle is started vaporizer 14 will be fully warmed up to remove water fuel or liquid particles during startup eec unit 11 controls current flow to cause vaporizer 14 to warm up much more power is applied to vaporizer 14 than to hego sensor 10 this will cause vaporizer 14 to heat much more quickly than hego sensor 10 vaporizer 14 will remove liquid fuel and water particles in the exhaust gas flow thus avoiding thermal shock to hego sensor 10 as emission standards call for faster light off hego sensor 10 will be heated at a faster rate thus increasing the risk of thermal shock as well as increasing the importance of vaporizer 14 referring to fig2 a vaporizer includes a ceramic resistance heating element 20 packaged in a hermetically sealed tube 21 made of a high temperature material the design of the.