Jaguar X Type: Rough Idle & Stalling Points to Bad Manifold

Having some experience with European diesel engines, I faced nearly identical symptoms on my 2009 Jaguar S Type Diesel. The check engine light came on, and engine performance dropped significantly with similar jerking during acceleration. My workshop diagnosed a leaking intake manifold caused by scorching, which was affecting the manifold pressure readings and air intake system. The symptoms perfectly match what you describe, rough running, stalling, and that distinct exhaust smell comes from air/fuel mixture issues. The complete repair, including parts and labor, cost me 1180€. The workshop needed 2 days to complete the work, mainly because they had to order specific parts. To help provide more specific guidance for your case, could you share: Current mileage on your X Type, Any prior manifold or air intake related repairs, Scan tool error codes if you have them, When the symptoms first appeared and if they get worse during cold starts The manifold issue is quite common on these engines when they age, and catching it early helps prevent additional engine performance problems. Regular cleaning of the air intake system can help prevent similar issues in the future.

Last service was done at 124779 KM and the engine misfire issues started shortly after. The scan revealed P0171 and P0300 codes, pointing to a possible air intake problem or gasket leak. The strong exhaust smell and rough running have definitely gotten worse during cold weather. My initial thought about the car manifold being the culprit seems supported by the manifold sensor data showing irregular pressure readings. Before replacing the entire assembly, I plan to have the workshop inspect the seals and gaskets first, since this could be a simpler fix if caught early. Based on the symptoms described, does this diagnostic approach make sense?

Based on your codes and symptoms, I can confirm this mirrors my X Type experience almost exactly. The P0171 and P0300 codes appeared on mine too, and that combination of engine misfire and manifold pressure irregularities is a classic sign of intake issues. When my workshop did the inspection, they found that while the gaskets were part of the problem, the manifold itself had developed hairline cracks causing the air intake system to pull in false air. Just changing gaskets provided temporary relief, but the complete manifold replacement was ultimately necessary. The cold weather sensitivity you mentioned is particularly telling, my car showed the same pattern. The thermal stress makes the air intake problems more apparent, especially during cold starts when the gasket leak becomes more pronounced. My suggestion would be to have them pressure test the entire intake system. In my case, they discovered the gasket leak was actually a symptom of the warped manifold rather than the root cause. You might save some money initially with just gaskets, but based on identical symptoms and codes, you are likely looking at a full manifold replacement soon. Keep monitoring your manifold pressure readings, if they continue to fluctuate even after gasket replacement, prepare for the larger repair.

Thanks for the detailed information about your manifold pressure readings and diagnostic codes. The check engine warnings combined with cold weather symptoms definitely align with my situation. I will follow your advice and have the workshop do a complete pressure test of the intake system before jumping to conclusions. The manifold sensor data continues showing irregular readings, so checking for both gasket integrity and potential manifold cracks makes total sense. If the engine misfire and performance issues persist after gasket inspection, I will proceed with the full manifold replacement to properly resolve the air intake problems. Better to fix it properly now than risk additional engine performance degradation. Thanks again for sharing your repair experience, it gives me more confidence in the diagnostic direction and helps validate the likely repair path needed to get my X Type running smoothly again.