Hello,
The check engine light is on on my 97 ES300. I've had the codes checked a few months ago and can't remember what they were, but the guy at the auto parts store suggested trying a new gas cap. Instead, I tried removing the cap and re-installing it and giving it several turns to make sure it was on tight. The light shut off. I finally got around to replacing the gas cap last week, and the same thing is happening: light goes on; I stop, remove and re-install the gas cap, and the light turns off for a few days and then comes back on. This pattern has repeated itself many times. My mechanic checked the codes last week and he told me it is a faulty mass air flow sensor, and that the removal / reinstalling of the gas cap is a coincidence. I'd rather not spend the $$ on a new air flow sensor if I don't need to; if anyone can explain why removing and re-installing the gas cap is turning the light off, I'd really appreciate your input.
Thanks,
John