[Porsche-O-Phile]

Yes, there's a procedure on Clarks - essentially you undo the nut on the front of the fuel rail (don't lose the ball bearing that's in there and don't do it while the system is under pressure) and then run the pump (jumper the DME relay) and collect the quantity of fuel over a known time interval to make sure you're flowing adequate fuel (forget the exact numbers offhand).

Other possibility includes the injectors which can be tested the same way.

Keep it simple - fuel, air, spark. Make sure you're getting all of them.