RepairPal Certified shops can diagnose and repair your 1996 Jaguar XJ6. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
Not gaping spark plug or if spark plug is worn out. I made a quick video on replace spark plugs on my 95 XJ6 https://www.youtube.com/watch?v=YasVAAJp6j0