How often: every 12,000 mi or year, whichever comes first. Eight plugs and long HT leads: misfires on a V8 are easy to miss until fuel use climbs.
Work safely: support the vehicle on axle stands, never a jack alone; let it cool first. Check figures against your workshop manual. You do this work at your own risk.
Parts
8 × Spark plugs (NLP100320 (genuine), gap per the handbook)NLP100320
Distributor cap & rotor or coil packs (if worn)
Tools
Plug socket with extension
Code reader
Multimeter
Step by step
Remove and check plugs one at a time so the HT leads stay in the right order.
Gap or renew plugs (NLP100320 (genuine), gap per the handbook). Check each lead (or coil pack boot) for cracks and resistance.
Distributor engines (14CUX): check the cap and rotor for cracks and tracking. Coil-pack engines (GEMS / Bosch): the timing is set by the ECU; read any misfire codes instead.
More Land Rover Discovery 2 4.0 V8 servicing
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