I bought a tundra 2005 in august '05. In the next 2 weeks the check engine appear every day. The dealer told me that is a problem with the gas cap so they change it. But 20 minutes after I left the dealer the light shows up again. I went three times again to the dealer and they can't resolve the problem.The number code say always the same, a problem with the fuel gases. If anyone knows what is the problem please let me know or send me an email to dovgsurvey@yahoo.com

What code are you getting?

I have a 2003 toyota tundra V8 and i have had the same problem. On the way to my last two scheduled maintenances at the toyota dealership, the check engine light has come on. I was amazed at the timing! Turns out that it was the gas cap that was detecting air escaping. The dealership replaced the cap and it solved the problem.

If it is not the cap, then it could be a vent line to the gas tank.