I will look at engine temps more closely at high alts cos this is happening to me too.
This initially happened to me when switching from drop tank, which was empty, to main tanks. The engine would just stop more or less and i would have to wait a bit, while pumping the hand pump, to get the fuel pressure back up. The engine would then start back up. The three times ive been up on the The Big Show campaign this happened to me. All three times when changing tanks and then also later on during the flight. All well above 25k.
All of a sudden the fuel pressure light would come on despite the switch being set to pressurize the tank and the only thing that makes the light go off and get the engine running again is using the hand pump till the light goes off.