UK Car Repair: 1995 XJ6 stalling.., transmission code, speed circuit

Question
I have a federal 1995 XJ6. Intermittently at either cruise or coasting, the engine will sputter and or stall, then display the "check engine" and "transmission" lights and the car goes into "Limp" mode if it stays running. I received fault codes P1775 & P727 (speed circuit no input). I've replaced the Crank position sensor, had the codes cleared, but alas, the problem has shown up again.

Can you help?

Regards,

Tony

Answer
P1775 is a transmission code and P0727 is simply confirming that the engine stalled. It may be a transmission problem and of course the systems are all interconnected so the Transmission module is telling the engine to stop/reduce torque.  Check transmission fluids/ connections etc.