Parts for your 1990 Mitsubishi Pajero-Spark plugs

1990 Mitsubishi Pajero spark plugs: what’s fitted and how to look after them

On a 1990 Mitsubishi Pajero, spark plugs are relevant for the petrol engines and not used on the diesel engines. Technical references including the Mitsubishi Pajero factory service manuals for late-’80s to early-’90s models, common workshop guides (e.g., Haynes Repair Manual for Pajero/Montero/Shogun), and ignition parts catalogues (NGK/Denso) list spark plugs for the petrol 2.6L 4G54 and 3.0L V6 6G72, while the diesel 2.5L 4D56/4D56T uses glow plugs instead. Diesels ignite fuel by high compression and heat, so they don’t need spark plugs.

For owners of a petrol 1990 Pajero, spark plugs do the vital job of igniting the air–fuel mixture in each cylinder. Fresh, correctly gapped plugs help the engine start cleanly, idle smoothly, pull strongly up hills, and sip less fuel. On older 4x4s that see towing or dusty tracks, the plugs can cop a hard life, so staying on top of them is smart preventative maintenance.

As a rule of thumb, standard copper plugs are typically replaced about every 20,000–30,000 km, while platinum or iridium options can often stretch to 60,000–100,000 km, depending on brand, tune, and conditions. Always follow the service schedule in the vehicle’s workshop manual and the plug maker’s recommendations. Check and set the gap to spec for your exact engine code (commonly around 0.8–1.1 mm, engine-dependent). If fitting new plugs, start them by hand, then torque to the figure in the manual to avoid thread damage. Use anti-seize only if the plug manufacturer specifies it, and go easy—over-lubing can distort torque readings.

Signs your Pajero’s plugs might be due:

• Hard starting, rough idle, or a stumble under load
• Higher fuel use, sluggish performance, or a misfire code on later ignition setups
• Sooty, oily, or eroded electrodes when inspected

Good practice during a service:

• Inspect plug leads/boots or coil-on-plug boots for cracks and carbon tracking
• Keep water and degreaser out of plug wells, blow out debris before removal
• Stick with the correct heat range and thread reach (cross-check via reputable catalogues)

These guidelines align with period Mitsubishi service literature and mainstream repair manuals, plus application data from established ignition component suppliers for the 4G54 and 6G72 petrol engines.

FAQ: 1990 Mitsubishi Pajero spark plugs

Does a 1990 Mitsubishi Pajero use spark plugs?
Petrol models (2.6L 4G54 and 3.0L V6 6G72) use spark plugs. Diesel models (2.5L 4D56/4D56T) use glow plugs and have no spark plugs, as combustion is by compression ignition. This aligns with Mitsubishi factory service manuals and mainstream repair/parts catalogues.

How often should the plugs be replaced?
For most 1990-era petrol Pajeros, copper plugs are commonly changed every 20,000–30,000 km. Platinum/iridium types can go longer—often 60,000–100,000 km. Heavy towing, short-trip city work, or dusty off-road use may shorten intervals. Always confirm with the workshop manual and the plug maker’s spec.

What plug type and gap should be used?
Use the correct thread reach, heat range, and resistor type listed for your exact engine code in a trusted catalogue. Set the gap to the Pajero engine spec found in the service manual, many sit around 0.8–1.1 mm depending on engine. When in doubt, follow the plug manufacturer’s data for the 4G54 or 6G72.