We have a '99 Lexus RX300 with 174,000 miles (the engine has 130,000). The check engine light has been on for 2 years. The first mechanic found it was an O2 sensor and said that we didn't need to really do anything as long as the car was running good. So we didn't. Apparently a new code appears when running a diagnostic for the evap. sensor or vapor canister...is that right??? We had the evap sensor fixed..or so we thought and than tried to have the vapor canister worked on but the mechanic said the light came on. Recently, the car has started lurching or losing power when it's warmed up and when it's accelerating. So, we took it to the Lexus dealership and 2 things were suggested 1) the vapor canister had been installed incorrectly and 2) sounds like the transmission is going. So I have 2 questions, I think, 1) What is going on with the check engine light? 2) Does this sound like the transmission is going? Oh and a third...What should we do???