I hear if you drill a very small hole in the side of your gas tank, this popping will stop.
---------- Post added at 06:56 AM ---------- Previous post was at 06:43 AM ----------
In reality if this happening right after refueling it's probably the evac system vapor vent valve. It's an emissions requirement. To put it simply as your fuel tank empties or fills it has to either let let air in or out. In the old days, there was just a open vent that allowed air to come in and out freely. Emissions controls requires a regulated valve that opens and closes only when it's needed. When you fill up, the PCM recognizes this and your vapor vent valve will close or open as necessary. Additionally, the system will do an "IBIT" initial bit check as certain states to check if the system is in good working order. Some manufactures this IBIT happens every time you start, others when you fill your car up...... so my guess is that your system is conducting an IBIT of the evac system. Your solenoid for the vaptor vent valve is probably just really loud or it's starting to fail. When it does fail you'll get a code.
just my guess.
