I have a 2008 G35xS. I have approximately 5,000 miles on the car. When the car had 2,900 miles the check engine light went on. Since I live about 125 miles from the nearest dealership I waited to take the car in until the 3,500 maintenance. The dealership did the reading and could not find a reason why the light went on. They claim it was a ghost reading. They reset the light and performed the schedule service. Well, everything has been going well until 4,950 miles. The light is on again. I have checked the gas cap and it is firmly tightened. Has anybody had this problem?

take it back to the dealer - they need to fix it. not a completely uncommon issue. i'm sure it's one of the sensors fouling up. resetting it won't help.