Yesterday morning I took off to town to sit in a 3 hour line to get gas (due to IKE)! About 2 miles down the road the check engine light came on. So when I got in line for the gas I pulled the hood and check to make sure all the fluids were full. Truck was running fine so I didn't worry about it. Well today my parents took the truck to sit in the 3 hour gas line again (filling up 55 gallon drums). So they went ahead and topped off the truck as well. When they dropped it back off the Gas Cap light is on. I took it off and retightened it but the light stayed on. Could the check engine light and gas cap light be on because of the same problem? And is the gas cap the most common problem? Also the dealers all around are closed down so does anyone know how much a cap cost?

Thanks,
Robert

 

It sounds like the gas cap seal is bad. You can google to find a new one. They shouldn't be that bad to replace. Red

 

Scan the computer to see what is wrong. It won't just go out if the gas capped sealed until it see's a bunch of drive cycles without the problem.

 

Thanks guys I pulled the code and it gave me a P0440. Then I took the battery loose to reset the computer. I started it up and didn't have either light on but havent taken it out for a test drive yet.

 

P0440 is a General Evap System Failure

So I would check the Gas cap seal then crawl under and check the Evap unit for any obvious sign of failure.

Hope its just a seal or broken line, and stay safe down there