It does sound like the fuel pump. The 'clunk' could be anything else as that rear can be quite vocal.
If it is the pump then replacing it is relatively straightforward. Then make a note that only ethanol free high octane fuel is to be used for ever after...
Michael, I too think the “clunk” (which in retrospect may have been more of a “feel” of the rear responding to the sudden loss of throttle) was just inertial and not the actual problem.
This morning, after letting her cool down, I hit the inertia switch again, and tried the ignition. The fuel pump had life but sounded like more of a low growl than the usual higher-pitched buzz. The engine caught for 3 or 4 seconds and then died. Repeated tries just resulted in shorter successes, so I do think it is the fuel pump dying. Will get towed to the dealer (still under warranty) in a couple of days. Have read about other pump failures. Wish there was a more robust substitute!
Also Michael, I have seen your warnings about ethanol in the past, but it is damn hard to find gasoline without it here in my area. The stations are few and far between.
