engine light on and off on 2001 Jaguar S-Type

engine light came on diagnostic coil6 even replaced then the
engine light off, drove it for45 miles engine light came on again drove it for 15 miles in two days engine light off. car runs good no smells what is wrong. called mechanic said bring car to scan it again.i will after 20 miles if light comes on again.

Asked by for the 2001 Jaguar S-Type
Intermittent ignition coil is common on the 4.0L I had one that would buck and surge and not even set a Check Engine Light identifying which coil was failing. Some shops just replace all coils if it doesn't identify which coil has failed and a drivability problem is experienced.
I have a 2000 S-Type and I am experiencing the same problems. However, I am replaced the damaged engine coils and I'm still having the same problems with miss-fires. A mechanic said it all 4 timing chains need to be replaced at an astronomical price. Do you have any suggestions/advice?