Wanted to conclude...
Last weekend decided to replace the fuel tank rubber sleeve... the one I'd been sitting on for months, and with that occasional waft of fuel and ever-resident CEL... denoting the P0455 code.
Removed the two fuel connections... the vent tube... and electrical connector.
Removed the lock ring... that can be a bugger... and used a pry bar to encourage it out.
Pulled up the fuel pump/sending unit... a couple/few inches... and there was the original (or however old it was, not replaced in the 6.5 years I've owned it, rubber sleeve. (Porsche Sealing Ring for Fuel Tank Level Sensor Uro Parts 1J0-919-133 A Pelican Parts site). Anyhow...
That ring had somehow become dislodged for it was resting, askew, above the sending unit/pump appliance. Clearly that was from where the wafting originated. Since I had to remove the battery the P0455 was cleared, no biggy.
I've since driven it ~100 miles... 10 drive cycles or so... and no code has emerged. The OBD2 reader I carry reveals no pending.
I discovered that installing that rubber ring first into... atop the tank made for an easier reinstall of the unit. I had installed the rubber ring onto the unit... then attempting to snug it into the top of the tank. That didn't work... for ridiculous while. With the rubber ring first installed into/atop the tank... the unit slid right in.
Thankfully it didn't, or hasn't yet again sprung the P0455 code. If it pops up I know I'll then have to begin looking at the fuel filler tube on down. Evap country. Then the smoke test, and an update.
