1998 Jaguar XJ8 Misfire with P0175 and P0171 Codes: Diagnosis and Fix

Model: 1998 XJ8 Jaguar Fault Code: P0171 Posted: 2013-08-09 10:50

I'm experiencing a noticeable misfire on my 1998 Jaguar XJ8, accompanied by diagnostic trouble codes P0175 and P017-than. I've already replaced the spark plugs, inspected fuel injectors for clogs, checked for vacuum leaks, and installed new MAF and O2 sensors. The engine runs smoothly when accelerating or in passing gear, but exhibits a misfire at idle and during high gear operation. Despite these efforts, the issue persists. What could be causing this, and what is the most effective solution to resolve both codes and restore smooth idle performance?