Ignition High‑Tension Lead (Cylinder 4) for Subaru

? This high‑voltage ignition lead is a key link between the ignition coil and the spark plug on cylinder No.4. It is needed to deliver a strong, clean spark at the right moment, helping your engine start easily, idle smoothly, and pull with proper power.

How it works

⚡ When the coil generates high voltage, this cable carries it through a thick insulated core and noise‑suppressing conductor to the spark plug terminal. The boots seal tightly to keep moisture out, while the internal resistance helps reduce radio interference and protects ignition components from voltage spikes.

What happens if it’s broken

? A worn or cracked lead can leak spark to ground, especially in damp weather. That causes misfire, rough idle, hesitation, hard starting, poor fuel economy, and may trigger a check‑engine light. Continued driving can overwork the coil, foul the plug, and harm the catalytic converter from unburned fuel.

Service tips

✅ Replace if you see arcing marks, brittle insulation, swollen boots, or if cylinder 4 misfire follows the lead. Always push boots until they click and keep routing away from hot exhaust parts.

Compatibility

• Legacy
• Impreza
• Forester