My 2003 Altima is running great but the service engine came on.This is the third time in 6 months.I tighten the gas cap before and had a sensor replaced before and the light went off.This time time I tighten the gas cap and it is still staying on. I don't want to spend money for nothing when it seems to be running great.Is there anyting I can check or do.

Thanks

Mike

You can take it to a shop which will connect the car to a computer and check which error code caused the check engine light to come on. I don't know if it's free everywhere, but I know there is a Honda service center here in Croatia that does it for free (for Hondas).

Engine service soon light is different with Check engine light.
May be it needs evaporative control valve replaced which is under gas tank.