So the thread on "Engine out practice" got me thinking about how I've always wanted to run a tank dry (obviously with gas in another tank), so I tried it this morning. I know some people, in an attempt to maximize range, do this regularly. My warrior holds more gas for much more flight time than I'm willing to sit in the plane at one time, so I have never felt a need to do this for range. But, I still wanted to try it. The results were not what I expected: I've heard that when the tank reaches empty/starts sucking air, the fuel pressure gauge gets erratic then the engine quits. All true, but a bit of an over simplification. In my warrior, I have two tanks (L/R) a fuel pressure gauge, a JPI fuel monitor, and both mechanical and electric fuel pumps. So today at a very high altitude, I let one tank run dry, with just the mechanical fuel pump working, and the electric pump off. Of side note, my JPI seems to work very well. I had run on the left tank for 1.5 gallons just to be sure all was well in that tank, before switching to the right and running it dry. The JPI indicated 18.9 gallons (Warriors have about 1 gallon unusable) on the 18 gallon tank when I noticed the pressure gauge drop, to about half of its normal reading. At the first sign of the pressure drop, I watched the gauges but left everything alone. The plane flew on, making normal power for about 30-45 more seconds, before it slowly started to lose power over about 20 seconds. While this was going on, my JPI fuel monitor went nuts, indicating 30+ gph fuel burn, setting off the low fuel warning (mine is set to warn if there is less than an hour of fuel). I assume it read this high because there was air in the line instead of fuel. As the engine lost about 50% power, I turned on the electric fuel pump, and the engine went back to normal power for another 10 seconds or so, before finally dropping to idle. When it dropped this second time, it was nearly immediate. Leaving the electric pump on, I then switched over to the nearly full tank, and the engine fired back up, also nearly immediately. I've heard that normally it takes some time for the gas in the other tank to reach the engine, so I was expecting some glide time, but it went back to normal power/normal fuel pressure in 2, maybe 3, seconds. When I got back on the ground and to the hangar, I tried switching back to the empty tank, but the engine died somewhat quickly. I then tried draining the "empty tank" with the quick drain. About a quarter gallon was still able to come out the quick drain (this makes sense and is what I would expect, as I would think the quick drain needs to be lower than the fuel pickup tube for water/sediment reasons).