Parts for your 1998 Subaru Forester-Ignition coils

1998 Subaru Forester ignition coils

According to the Subaru Factory Service Manual for MY1998 Forester (Ignition section) and Subaru’s Electronic Parts Catalogue, the 1998 Forester (EJ-series engines) uses a two-channel ignition coil pack with high-tension leads. Major aftermarket catalogues from NGK and Denso also list a dedicated coil pack for this model year. So yes—ignition coils are fitted and relevant for the 1998 Subaru Forester.

The ignition coil pack on a 1998 Forester transforms the battery’s 12 volts into the high voltage needed to jump the spark plug gaps under load. On this model it’s a wasted-spark, dual-output pack that fires pairs of cylinders and feeds spark via traditional leads. Working with the ECU, crank and cam sensors, it times and amplifies the spark so the EJ engine starts crisply, idles cleanly, and pulls smoothly up hills.

Coils aren’t a scheduled replacement item, but they’re worth a check every service—especially on a 25-year-old Forester. The big killers are heat, vibration, and moisture. During routine servicing, they should look for hairline cracks in the housing, carbon tracking, or white/green corrosion at the terminals. Keeping quality spark plugs and leads in good nick reduces coil stress, so sticking to the correct plug spec and intervals is smart maintenance.

• Common symptoms of a tired coil pack: rough idle, hesitation under load, hard starting, poorer fuel economy, and a flashing or steady check engine light.
• Typical fault codes: P0301–P0304 (misfires) and sometimes P0351–P0352 (ignition primary/secondary circuit).
• Quick checks: inspect the leads for brittleness, ensure boots fit firmly, and look for arcing marks around the coil towers at night with the engine running.

When replacement is due, it pays to confirm the diagnosis first—rule out worn plugs and leads. Fit an OEM or reputable aftermarket coil pack, transfer leads one by one to avoid mix-ups, and use a smear of dielectric grease inside the boots. Mount the coil securely and tighten hardware to the factory spec listed in the FSM. After installation, clear any stored codes and take a short road test to confirm the misfire is gone.

As preventative care, keep engine earths clean, ensure the coil’s mounting area is dry, and avoid pressure-washing the engine bay. With decent plugs and leads, a good coil pack often runs happily for 150,000–250,000 kilometres or more.

FAQs

Does a 1998 Subaru Forester use coil-on-plug?
No. It uses a single dual-output coil pack with high-tension leads. Later Subarus shifted to coil-on-plug, but the 1998 Forester stuck with a central pack design.

How often should the ignition coil pack be replaced?
There’s no fixed interval. Replace when there are symptoms or fault codes and testing points to the coil. Many originals last 150,000–250,000 kilometres, regular inspections help catch issues early.

What are the tell-tale signs of a failing coil on a 1998 Forester?
Misfires under load, rough idle, hard starting, worse fuel economy, and codes like P0301–P0304 or P0351–P0352. Visible cracks or arcing marks on the pack or leads are also red flags.