Car is missing. Changed spark plugs, changed coils. It starts missing on backing up.

What is your question?

Almost every thing has been done to fix the car but it still misses and the engine light comes on immediately. New spark plugs, all new coils. It still stutters on backup and the engine light comes on when starting. Then it runs smoothly. There are no noises or leaks. Could this be the fuel cap?

What makes this problem better or worse?

Usually when the car is cold but not always.

How long has your 2005 Jaguar XJ8 had this problem?

Several years off and on.