New (to family) 2012 malibu with 2.4L

[irv]

Is your son "topping off" or just removing at the first click off when filling?

I believe he stops at first click as I told him to do that but knowing him and trying to get the most in his tank, especially when gas is cheap, he may squeezing in as much as possible? I'll ask him again.
Curious, however, what you are getting at?

 

[KCJeep]

Just wondered if perhaps he was causing the purge valve to freak out by topping off. Particularly since it seems to coincide with fill ups.