Ignition Coil + Iridium Spark Plugs for Mazda MX-5 Miata (1999-2000) 1.8L

Direct-Replacement Ignition Coil and Iridium Spark Plug Kit for 1999-2000 Mazda MX-5 Miata (NB)

What it Does: The ignition coil and iridium spark plug kit restores primary and secondary ignition energy on the 1999-2000 Mazda MX-5 Miata to eliminate high-RPM spark blowout and resolve rough idle conditions caused by secondary circuit breakdown.

The Stock Mazda MX-5 Miata Ignition Degradation

Factory waste-spark coil assemblies on the second-generation NB Miata are mounted at the rear of the cylinder head, directly against the firewall. In this high-temperature zone, sustained thermal cycling degrades the coil's internal epoxy potting and fine primary copper windings. This leads to dielectric failure, intermittent secondary voltage leakage, and unmetered misfires under heavy engine load. Paired with aged spark plugs whose widened gaps demand higher ionization voltage than tired stock coils can deliver, the BP-4W engine suffers from sluggish throttle response, unburnt hydrocarbons, and power drop-off near the 7,000 RPM fuel cut.

The Engineering Solution

This ignition service pack features a direct-fit dual waste-spark coil pack engineered to match factory dwell timing and discharge profiles, replacing OEM numbers like BP4W1810XB and UF343. High-dielectric epoxy resists thermal fatigue, preventing casing fractures and voltage arcing. Paired with fine-wire iridium spark plugs, the setup requires significantly lower firing voltage to initiate flame-front propagation. The small-diameter iridium center electrode ensures stable spark kernel development under varying cylinder pressures, restoring crisp transient throttle response and complete combustion efficiency.

Technical Specifications

Compatibility

• 1999 Mazda MX-5 Miata Base 1.8L L4 Gas (NB)
• 1999 Mazda MX-5 Miata 10th Anniversary 1.8L L4 Gas (NB)
• 2000 Mazda MX-5 Miata Base 1.8L L4 Gas (NB)
• 2000 Mazda MX-5 Miata LS 1.8L L4 Gas (NB)
• 2000 Mazda MX-5 Miata Special Edition 1.8L L4 Gas (NB)

Frequently Asked Questions

Does this fit the NB MX-5 Miata?

Yes, this is a direct fit for the 1999-2000 Mazda MX-5 Miata equipped with the 1.8L BP-4W engine.

Are spark plug wires included with this kit?

No, this replacement service package includes one waste-spark coil assembly and four iridium spark plugs; plug wires are sold separately.

The Mazda Roadster Standard

High-revving naturally aspirated JDM engines demand clean, uninterrupted spark to preserve throttle precision and balanced power delivery throughout the rev range.