Why might you smell gas fumes inside a 2001 Kia Sportage?

I had the same problem on my 2001 EX, usually when it was cold out, I would smell raw gas fumes. there is a spring clamp on the fuel pressure regulator intake, simply replace it with a flat spiral type clamp you can get at any hardware store or Home depot for 39 cents. when it's cold the spring type doesn't seal properly between the rubber hose and the metal pipe. when it warms up, it seals. just change the clamp.

Also might be the back door is not closing full enough to seal against the rubber edge , and the vaccum sucks up the fumes inside!.