Parts for your 1999 Subaru Forester-Ignition coils

1999 Subaru Forester Ignition Coils

Technical sources including the Subaru Forester MY99 Factory Service Manual (Ignition System section), the Haynes Service & Repair Manual for Forester SF, and major aftermarket catalogues from NGK and Hitachi confirm the 1999 Subaru Forester runs a four‑tower ignition coil pack in a wasted‑spark setup. It’s mounted on the intake manifold and uses high‑tension leads to each plug, rather than individual coil‑on‑plug sticks. So yes, ignition coils are absolutely relevant on this model.

The ignition coil’s job is simple but critical: it transforms the battery’s low voltage into the high voltage needed to fire the spark plugs under compression. On the ’99 Forester’s EJ‑series petrol engines, the coil pack fires two cylinders at once (wasted‑spark), delivering consistent ignition timing for smooth running, decent fuel economy, and reliable cold starts.

When the coil pack starts to go, drivers may notice rough idle, hesitation, flat spots under load, harder cold starts, or a flashing check engine light. Fault codes may include misfires (P0301–P0304) or coil primary/secondary circuit faults (P0351–P0352). Visual checks for case cracking or carbon tracking, testing primary/secondary resistance to factory specs, and swapping leads/plugs side‑to‑side can help confirm a diagnosis before replacing the coil.

• During routine servicing, inspect the coil pack for cracks, oil contamination, and white tracking marks. Heat and vibration under the bonnet can age the resin housing.
• Keep the spark plugs and leads on schedule. Fresh plugs and quality leads reduce stress on the coil and improve spark energy.
• Avoid pressure‑washing the engine bay, water ingress can accelerate coil failure.
• If replacing the coil pack, use a reputable brand and follow the correct lead routing (Forester EJ firing order 1‑3‑2‑4). A dab of dielectric grease at the boots helps future removal and keeps out moisture.
• After fitment, clear codes and road‑test under load to confirm the fix.

Coils aren’t a “replace by kilometre” item, they’re replaced when testing or symptoms point to failure. With quality plugs, good leads, and sensible servicing, the 1999 Forester’s coil pack generally delivers years of faithful service across Aussie and Kiwi conditions.

Does a 1999 Forester use a coil pack or coil‑on‑plug?

It uses a single four‑tower coil pack in a wasted‑spark setup, not individual coil‑on‑plug sticks. The pack sits on top of the intake manifold with leads running to each plug.

What are the common signs the coil pack is failing?

Misfires under load, rough idle, harder cold starts, poor fuel economy, and a check engine light are typical. Cracks on the housing or carbon tracking, plus codes like P0351–P0352, often back it up.

Should the coil pack be replaced as preventive maintenance?

No, it’s not a scheduled replacement item. Focus on timely spark plug and lead changes, keep moisture away, and test the coil if symptoms appear. Replace the coil only when fault‑finding confirms it.