I've had the EV mode switch installed since the day I bought my Prius. Its great for coasting down the hill when I first start out, or to move it around my garage / driveway. But yesterday, I wanted to see if I could make it home (2-3 miles, mostly downhill) in EV mode. So as I was driving, I puched the button, it beeped twice meaning it wasn't going to engage, and I pushed it again, just to show it who the boss was. The EV mode did not engage, but now everytime I let go of the gas pedal (car warm, under 45 mph, battery above 2 bars) the engine shuts off instantly! Normally, my engine will stay running till I've stopped for a few seconds, or if I'm on the brakes for a few seconds, under 35 mph, but it never shut down as soon as I was off the gas pedal. I usually average about 56 mpg driving 35-45 around my house, but yesterday I was averaging above 75! I even drove in a three mile circle to ensure it wasn't just from driving down hills. I continued to drive for 45 minutes and consistantly got better than 75mpg. I did it again at lunch today! Is this something we know about?