I have a Check Engine Light on. Had it checked. The guy said it was to do with the Gas Cap needing to be replaced for starters. What else is involved in that System if it is not the gas cap? Just came off a very long trip and got 26.5 mpg with the light on.
Where else could the problem be? The light showed up around 50,000 miles and now have 54,000. Coming up for an inspection by the state. I can get a waiver due to my age but I will be limited to 5k per year. Insp. is every 2 years.

Charcoal EVAP system, which can be damaged if you try and overfill your gas tank. When the pump handle cuts off, don't try and force more gas into the tank. The excess can dump raw gas, instead of fumes, into the EVAP system. Likely, it's just a leaking gas cap.

Charcoal EVAP system, which can be damaged if you try and overfill your gas tank. When the pump handle cuts off, don't try and force more gas into the tank. The excess can dump raw gas, instead of fumes, into the EVAP system. Likely, it's just a leaking gas cap.

Thanks TGM, Is there a photo of a Evap System? I have not replaced the gas cap but have inspected it and it seems to be soft on the "O" Ring and not hard. Tech cranked down very hard on Gas Cap and reset the light but it came back on about 10 miles down the road. Will replace the GC and get it set again. It might be a valve in the gas cap that is leaking and not the "O Ring".

Sorry, I don't have a picture.

Sorry, I don't have a picture.

Thanks, I found a very good explanation of a EVAP System

www.aa1car.com/library/evap_system.htm