I mostly fly on autopilot, and work on another computer next to my flight PC. Just not enough time in the day to do both separately. I keep my headphones on so I can listen to ATC and hear problems (I use FSPassengers which give me a 5% chance of having some sort of failure, and tracks my flights neatly for me).Anyways, this has happened on every flight I've taken this bird out on.For some reason, power to the engine drops. The engines don't shut down or anything, but manifold pressure disappears and the tachometer drops to 10. The plane then stalls as its trying to hold altitude with AP and I hear the stall horn with my headphones on. I'm at around 8 - 11000 feet when this happens.No idea what fixes this issue or what is causing it. Eventually it just figures its self out and power returns to normal. But I haven't a clue why.Thanks in advance for any advice on how I am probably flying this bird wrong.