Parts for your 2008 Mitsubishi Lancer-Spark plugs

2008 Mitsubishi Lancer spark plugs — what they do and when to replace them

Based on technical references such as the Mitsubishi Lancer Owner’s Manual (2008), the Mitsubishi Service Manual for the 4B1-series engines, and major plug catalogues from NGK and Denso, the 2008 Mitsubishi Lancer petrol models (2.0L 4B11, 2.4L 4B12, and the turbocharged 4B11T in Ralliart/Evo X) are all fitted with spark plugs and list them as routine service items. Only the Europe-market 2.0 Di-D diesel variant uses glow plugs instead, not typically sold in Australia or New Zealand.

For a 2008 Mitsubishi Lancer running a petrol engine, spark plugs are the small-but-mighty parts that kick off combustion in each cylinder. Every time the piston comes up, the plug fires a precise spark to ignite the fuel–air mix. In the Lancer’s coil-on-plug setup, each cylinder has its own ignition coil sitting on top of an iridium long‑life plug, chosen by Mitsubishi for reliable firing, clean burn, and fewer changes over the car’s life.

As part of regular servicing, it’s smart to check plug condition and replace them as a full set. Mitsubishi’s schedules and the plug makers’ catalogues put iridium plug life in the long‑service bracket — often around 100,000 to 160,000 km depending on spec and driving conditions. Turbo models (Ralliart/Evo X) and cars driven hard, on lots of short trips, dusty roads, or on LPG may need earlier changes. Always match the exact spec and heat range shown in the handbook or under‑bonnet label, common OE equivalents are NGK and Denso iridium types for the 4B11/4B12, with colder heat ranges for the turbo 4B11T.

When fitting, work on a cool engine. Use a proper thin‑wall spark plug socket, thread each plug by hand first to avoid cross‑threading, and torque to factory spec (typically in the 18–22 N·m window for these engines — check the service manual). Iridium plugs are usually pre‑gapped, the Lancer generally runs a 0.7–0.8 mm gap. Avoid levering on the fine iridium tip, and don’t slather anti‑seize on modern nickel‑plated plug threads (plug makers note it can lead to over‑tightening). A dab of dielectric grease inside each coil boot helps future removal and keeps moisture out.

If the Lancer starts to idle roughly, hesitates on take‑off, uses more fuel, or flashes the check‑engine light with misfire codes, tired plugs are a usual suspect. Fresh, correctly gapped iridium plugs bring back crisp starts, smoother running, better economy, and lower emissions — exactly what the service manuals, and the plug catalogues, are aiming for.

• Typical signs of worn plugs: hard starting, rough idle, flat spots under load, higher fuel use, and misfire codes (P0300–P0304).
• Replace as a full set and stick to the factory heat range and plug type.

FAQs

How often should spark plugs be replaced on a 2008 Mitsubishi Lancer?
For the petrol models with iridium plugs, plan on about 100,000–160,000 km under normal conditions, with earlier changes on turbo models or severe use. Always follow the service schedule in the owner’s handbook for the exact interval that matches the engine and local conditions.

What spark plug type and gap does a 2008 Lancer use?
Petrol 4B11/4B12 engines typically specify long‑life iridium plugs, with a factory gap around 0.7–0.8 mm and a model‑specific heat range. Turbo 4B11T uses a colder heat range iridium. Check the sticker under the bonnet or the service manual for the exact part code and gap for the specific trim.

What are the symptoms of worn spark plugs in a Lancer?
Expect harder starting, a lumpy idle, hesitation on acceleration, increased fuel burn, and sometimes a check‑engine light with random or cylinder‑specific misfire codes. If those pop up and the plugs are getting on in kilometres or years, fresh plugs are a smart first step.