Jaguar XK Stalling Issues Point to Fuel System Fix

As someone with moderate experience in car maintenance, I dealt with nearly identical issues on my 2012 Jaguar XF. The symptoms you describe match my experience exactly, rough idling, reduced power, and persistent check engine light. After diagnostic testing, my workshop identified a defective high pressure fuel pump as the root cause. The car sensors were showing irregular fuel pressure readings, which significantly impacted fuel economy. The repair involved replacing the entire high pressure pump assembly and recalibrating the fuel regulator system. Total cost was 1510€, and the repair took about 6 hours. Since the fix, the engine has been running smoothly with no issues. However, before jumping to conclusions about your XK, it would be helpful to know: Current mileage on your vehicle, Any recent fuel system maintenance history, Whether you notice these issues more during cold starts, What error codes your diagnostic scan revealed, Type of fuel you typically use This information would help determine if your situation truly mirrors what I experienced. While fuel system issues often share similar symptoms, pinpointing the exact cause requires specific vehicle details. Consider having a professional diagnostic test done, it saved me time and potentially unnecessary parts replacement by identifying the precise issue.

Agreed, had my last service at 78000 KM and currently at 80406 KM. The diagnostic scan showed error code P0171 which points to a lean fuel mixture. Had the fuel pressure tested and it was indeed fluctuating outside normal parameters. The engine misfire is most noticeable during cold starts. Symptoms match what you described perfectly, especially the rough idling and significant drop in fuel efficiency. My check engine light has been consistent since these issues started. Been using only premium 98 octane fuel since purchase. No prior fuel system repairs except routine fuel filter changes during scheduled maintenance. Based on your repair experience, seems worth investigating the high pressure pump assembly.

Thanks for the additional details, your symptoms and diagnostic results match my XF case even closer than I initially thought. The P0171 code and pressure fluctuations are exactly what I experienced. The high pressure fuel pump failure tends to worsen during cold starts because thats when precise fuel pressure control is most critical for proper fuel injection. Based on your mileage and maintenance history, this timing for a fuel pump issue makes sense. When my fuel pump was replaced, the mechanic also recommended updating several associated car sensors and replacing the fuel filter as preventive maintenance since the system was already opened up. This comprehensive approach helped ensure optimal fuel efficiency after the repair. One thing I noticed post-repair was a significant improvement in cold start behavior. The engine went from that rough, unstable idle to smooth operation within seconds of starting. My fuel consumption also returned to normal levels once the new pump was properly regulating fuel pressure. Since you're seeing the same error code and symptoms, I strongly suspect youre dealing with a similar high pressure pump issue rather than just a fuel regulator problem. Getting the pump assembly replaced should resolve the power loss and idle problems youre experiencing.

Based on your helpful insights and matching symptoms, I will schedule a diagnostic appointment this week to have the high pressure pump assembly checked. The similarities between your repair case and my situation are too specific to ignore, especially the P0171 code, cold start rough idling, and pressure fluctuations. Looking at the 6-hour repair time and 1510€ cost you mentioned, I will budget accordingly and plan for potential sensor updates while the system is being serviced. This seems like the most logical approach given the age and mileage of my XK. The persistent check engine light and engine misfire during cold starts have been particularly concerning. Knowing that replacing the high pressure pump assembly resolved these exact issues in your case gives me confidence about pursuing this repair path. Will update the forum once I have the work completed to confirm if this resolves my fuel injection problems and improves overall fuel efficiency.