I am on the 2nd rinse phase on my lexus right now(170k miles), the car had 136k when I purchased it and there was a check engine light that would not go away, after spending close to $1000 I gave up. When I came across auto-rx I thought I would give it a try. The real results came during the 2nd rinse phase(I am 1000 miles into the 2nd rinse phase btw) the check engine light dissappeared. Amazing how auto-rx works! Thanks for making a great product!!
Sometimes error codes are generated because sensors are not getting consistant readings. Could have been an error in the oil sending unit perhaps. Glad to hear that your light has found peace. I take it you will be running a maintenance dose in the Lexus.
Whatever your error code was, it will still be stored in the engine's computer. It could be something as simple as not having the gas cap on tight enough. Then when your computer decides to run an evaporative emissions cycle to test the fuel system for evap leaks, it could have detected this small leak. The light will then stay on until it runs that test again successfully finding no leak the next time. Then the light may go off, but the error code will still be stored. So, if you are curious (I know I am), swing by one of the auto parts stores that reads the codes for free and see what they come up with. Usually you can ask them to erase such codes as well. Then we may all learn a little something here.
Ok, on another thread I see where your Lexus is a 95, so having the codes read for free will probably not be an option. 96 was the first year for OBDII universal code reading. A 95 will probably still require proprietary code reader software.