i have a 98 nissan altima and the service engine light came on i took the car to my local mech (not the dealer) and he said that i needed to have the boost sensor replaced, well everthing went well, i drove the car home and on the way the engine light came on again and i returned to the mech, his little diagnostic tool indicated that my car was ok to drive and could not find anything wrong. so he reset it and the light did not come on again until driving to work the next morning. also when i fueled the car after the sensor was replaced the gas began to back splash. does one have anything to do with the other also i know there is another boost sensor in the back by the fuel tank. the part number is PS64-01 and it also has a 8342 imprinted on the sensor. yes i have the one he supposedly took out of my car. can someone please shed some light on this it seems know one can assist me.