Jaguar Repair: 2001 Jaguar S-type sputter, jaguar s type, change over valve

Question
I own a 2001 S-type 3.0, for the past month or so I've noticed when I pull up to a red light the car sputters, I thought at first it was bad gas or something but when I'm on the highway doing over 55, the car violently sputters unless I drive below 50 mph. This is driving me crazy can you please tell me whats going on.

Answer
There are several possible causes to your problem. 1. A bad fuel pump, 2. bad fuel filter, 3. bad ignition coil, 4. bad fuel tank change over valve, if you have two fuel tanks, 5. bad ignition system.
Check fuel system, then check ignition system. I hope this helps. Sam.