I have a 01 kia sportage that when it gets cold outside less than 48 degrees f, I smell gas when I drive. Also when it gets cold I have a hard time getting it to take gas, when I fuel up. The check engine light comes on as well when this starts, I forget exactly what the code was but says something about emission? I reset it and it fine for a while but the problem keeps coming back. I have 97800 miles on it.
Rubber return line from fuel psi regulator to metal return line is leaking when cold.
The spring clamps do not stay tight when cold and when the rubber expands when hot it seals.
Remove the upper part of the intake and replace the spring clamps with screw type clamps.
Had the same thing on both my Kia's. Theres fuel fumes in that line or the fumes are from the tank. You only notice it in winter because the heater intake is just behind there. When you speed up the draft blows the accumulation away, but the heater gets some. In the warm weather the clamp holds tighter.
It's pretty easy, take the 4 nuts that hold the plasic cover off, look to the passenger side of the engine, there are 2 tubes running along the top rail toward the front, with spring clamps. Replace them with flat hose clamps, you can get at Lowe's or home Depot for 45 cents each.