Rear Engine wants to Die!

[Jerry De Santis]

From your description, the engine is going lean. TIT rising while fuel flow drops. Sound like it can be your engine driven fuel pump. Since it is not a constant problem perhaps on certain flight conditions the engine driven fuel pump gets hot and excess bypass occurs. Frankly, under the condition you have, I would have it check out asap and not fly it until problem is solved. Big problems start small.

Good luck

Jerry