[SHELLYJUDD]

Hello to all
Is there anyone out there that can help me. My Mustang's service enginge soon light came on and the guy at the auto parts store told me I needed a new gas cap??? This is so crazy I have never heard of anything like this he said it gave him a code 401 and that it would be expensive then he came back and told me that all I really need is a new gas cap?? I went and got the cap and the light is still on I was going to disconnect the battery when I get home but my question is how common is the gas cap thing or did I just get played??

Thanks
Shelly