Last week I got my 9th CEL in the last 6 months.
As with all the others, the gauges read normal and the drivability remains constant. The CEL has stayed on for anywhere from a few restarts in the same day to 9 days.
Bad thing is the car is due for emission testing next month so I'm going to be forced to have it checked. I still think its a faulty gas cap or fuel inlet tube sleeve. Whenever I unscrew the cap to the first stop, I no longer get that hissing sound.