Ignition Coil and Iridium Spark Plugs for Audi A8 (2003-2006) 4.2L

Direct-Fit Ignition Coil and Iridium Spark Plug Kit for 2003-2006 Audi A8

What it Does: The ignition coil and iridium spark plug kit restores factory spark energy and cylinder combustion efficiency on the 2003-2006 Audi A8 4.2L V8, resolving misfire codes and rough idle conditions.

The Stock Audi A8 Secondary Ignition Breakdown

In the D3 generation Audi A8, intense thermal saturation inside the 40-valve cylinder head leads to premature failure of factory pencil coils. The BFM 4.2L V8 engine utilizes tight cylinder packaging where sustained operating temperatures degrade internal coil windings and cause micro-fractures in the silicone insulation boots. Over time, dielectric breakdown permits secondary spark energy to arc directly to the cylinder head rather than across the spark plug electrode. Concurrently, factory plugs suffer electrode erosion and gap widening, increasing secondary resistance and forcing aging coils beyond their operating limits. This results in P0300-P0308 misfire codes, hesitations under throttle load, and unburned fuel saturating catalytic converters.

The Engineering Solution

This comprehensive ignition tune-up kit replaces failing components with eight high-dielectric pencil ignition coils engineered to match OEM 077905115P and interchange UF418 specifications. Manufactured with high-temperature epoxy potting and reinforced silicone boots, each coil-on-plug unit resists heat soak and prevents high-voltage flashover. Paired with fine-wire iridium spark plugs, the system requires lower primary firing voltage to initiate a stable, concentrated flame front. The laser-welded iridium core demonstrates superior anti-erosion properties under sustained heat, stabilizing cylinder idle dynamics, restoring responsive throttle tip-in, and preserving factory fuel economy.

Technical Specifications

Compatibility

• 2003 Audi A8 Base 4.2L V8 (D3)
• 2004 Audi A8 Base & L 4.2L V8 (D3)
• 2005 Audi A8 Base & L 4.2L V8 (D3)
• 2006 Audi A8 Base & L 4.2L V8 (D3)

Frequently Asked Questions

Does this fit the D3 A8?
Yes, this is a direct fit for the 2003-2006 Audi A8 equipped with the BFM 4.2L V8 engine.

Are these spark plugs pre-gapped for the 4.2L V8?
Yes, all included iridium spark plugs arrive pre-gapped to factory specifications for straightforward drop-in installation without risking fragile center electrode damage.

The Audi Precision Standard

Engineered to meet stringent European electrical thresholds, this complete ignition set delivers precise primary-to-secondary resistance to maintain full compatibility with Bosch Motronic ECU diagnostics, ensuring zero check engine lights.