Celica Forums General Discussion General Hissing from fuel cap

Hi all,

I've noticed a loud hissing noise when I open my gas cap to refuel. Sound of air rushing either in or out of the filler hole is the best way to describe it. Doesn't make this noise with the cap on, only once I remove to refuel.

I had an engine light with code P0420 and noticed a strong smell of gas while sitting at idle with the windows down (never when the windows are up). Replaced the cat, no more engine light but the smell persists. Suspect an EVAP related issue but I'm not entirely sure, just wondering if anyone else has experienced this?

Thanks