UK Car Repair: 1984 Jaguar XJ6 engine missing, air flow meter, 1984 jaguar xj6

Question
Hi William,  I'm having a newish problem with my car seeming to  misfire and sputter intermittently.  I've replaced the fuel filter and spark plugs wires.  Any idea?  I'm still able to drive it, though I put-put-put a lot of the time, when it suddenly smoothes out and I get a nice surge of power for a while.  Engine is original with 120,000 miles and checked recently for compression, which was OK.

Answer
It could be any number of things causing a lack of fuel.  The fuel pump going bad, the fuel regulator faulty, an air leak into the intake "AFTER" the air flow meter or a sensor etc etc.  If I were to
pick one I would start with the water temperature sensor on the inlet manifold,