DisclaimerJaguar XJ (X351) V8-5.0L SC Technical Service Bulletin # JTB00241 Date: 111025 Fuel System - Misfire/Hard Start/Rough Idle/Poor Economy No. JTB00241NAS1 25 OCT 2011 SECTION: 303 Engine Misfire / Injector Clogging / Air Intake System Cleaning AFFECTED VEHICLE RANGE: CONDITION SUMMARY: Situation: The engine may exhibit a misfire, poor fuel economy, hard starting, and / or a rough idle condition. The engine Malfunction Indicator Lamp (MIL) may also be illuminated with misfire Diagnostic Trouble Codes (DTC) P0301 through P0308 and P0316, depending on the affected cylinder(s), stored in the Engine control module (ECM). This may be caused by poor fuel quality or fuel contamination, leading to clogged fuel injectors and restricting the fuel injector flow rate. NOTE: After basic testing has been carried out (checking coil and harness for damage, checking injector harness connections, spark plug fouling, correct fuel pressure, no fuel filter blockages etc) and if no fault can be found