Parts for your 2002 Subaru Forester-Ignition leads

2002 Subaru Forester Ignition Leads: What They Do and When to Replace Them

Based on the Subaru factory service manual for 2002 Forester models with the EJ202/EJ251 engines, and backed by parts catalogues from Subaru and ignition specialists like NGK and Bosch, the 2002 Subaru Forester (non-turbo) uses a remote coil pack with high-tension ignition leads running to each spark plug. That means ignition leads are absolutely relevant to most 2002 Foresters sold in Australia and New Zealand. Note: some turbocharged or JDM variants moved to coil-on-plug modules, which don’t use traditional leads, but that setup isn’t typical for local 2002 non-turbo Foresters.

In this Forester, the ignition leads carry high voltage from the coil pack to each spark plug, ensuring a clean, consistent spark under load, rain, heat, and vibration. Good leads help the engine start easily, idle smoothly, pull well up hills, and keep fuel economy in check. Over time, heat and oil vapour under the bonnet can harden the insulation, increase resistance, and allow arcing, which shows up as misfires, hesitation, and higher fuel use.

As part of routine servicing, it’s smart to inspect the leads every service interval and consider replacement around 100,000 km or 5–8 years, earlier if there are symptoms or damage. A quick visual check for cracking, swelling, burn marks, or loose boots goes a long way. If you’ve got a multimeter, measure resistance end-to-end and compare to spec from the Subaru service manual, excessively high resistance means it’s time for a new set.

When replacing, go for quality suppression-type leads matched to the EJ-series engine. Fit one lead at a time to avoid mixing up firing order, push the boots fully home on the coil and plug, and route them in the original clips and separators to prevent crossfire. A pea-sized dab of dielectric grease inside each boot helps future servicing and keeps moisture out. It’s also a good moment to check spark plug condition and gap, as tired plugs can stress even new leads.

Done right, fresh ignition leads restore crisp starting, smoother running, and a happier Forester—especially on cold mornings and wet days.

• Signs your leads are tired: rough idle, misfires under load, visible arcing at night, or white tracking marks on the insulation.
• Helpful tip: if washing the engine bay, avoid soaking the coil pack and leads—moisture can sneak into boots and cause a temporary misfire.

Popular questions about 2002 Subaru Forester ignition leads

Do all 2002 Subaru Foresters use ignition leads?
Most non-turbo 2002 Foresters in Australia and New Zealand do, as documented in the Subaru service manual and aftermarket catalogues for EJ202/EJ251 engines. Some turbo or specific JDM variants run coil-on-plug systems, which don’t use traditional leads.

How often should ignition leads be replaced?
Inspect at every service and plan on replacement about every 100,000 km or 5–8 years. Replace sooner if there are misfires, cracking, swelling, burn marks, or out-of-spec resistance.

What happens if worn leads are left too long?
You may see harder starting, rough running, poor fuel economy, and potential catalytic converter damage from unburnt fuel due to misfires. Replacing leads early is cheaper than chasing knock-on issues later.