I have a 2002 ES 300. Sometime when I start it in cold weather it idles very rough, someitme to a point where the engine shuts off. Check engine light also came on and when it idles rought the check engine light flashes on and off. Took it to the dealer and all they said was that it could of been bad gas cause they couldnt find anything else wrong. I have ran the gas down and put gas again and it happened again. Does anyone have any suggestions?