Section 5 (Engine Controls - Tests W/Codes): Summary
WARNING: This page is about a different car, the 1992 Jaguar XJ6 and 1991 Jaguar XJ6. However, it is still accessible from the selected car via links, so may be relevant.
If no hard fault codes are present, see TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.