Bulkhead Workshop › Land Rover models › Range Rover Classic 3.5 / 3.9 / 4.2 V8 fuel injection › Workshop guide › Plugs, leads & ignition timing

Range Rover Classic 3.5 / 3.9 / 4.2 V8 fuel injection: plugs, leads & ignition timing

Ignition · Range Rover Classic (1970–96) · 1985–1996

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 (3.5 EFI: Champion RN9YC (ERR743) or RN12YC (ETC7244) · 3.9 catalyst: BP5ES type (GSP4382) · 4.2: RN11YC (ERR3799); gap 0.72–0.88 mm) ERR743 / ETC7244 / GSP4382 / ERR3799
• Distributor cap & rotor or coil packs (if worn)

Tools

• Plug socket with extension
• Code reader
• Multimeter

Step by step

1. Remove and check plugs one at a time so the HT leads stay in the right order.
2. Gap or renew plugs (3.5 EFI: Champion RN9YC (ERR743) or RN12YC (ETC7244) · 3.9 catalyst: BP5ES type (GSP4382) · 4.2: RN11YC (ERR3799); gap 0.72–0.88 mm). Check each lead (or coil pack boot) for cracks and resistance.
3. 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 Range Rover Classic 3.5 / 3.9 / 4.2 V8 fuel injection servicing