Showing specs for all NA & NB Miatas

Spark plug gap (NB1)

1.0–1.1 mm (0.040–0.043 in)

Factory manualTaken from a Mazda factory workshop manual, with page citation.
Procedure

Factory plug gap for the naturally aspirated engine; the Mazdaspeed plug has a separate smaller gap.

Applies to
  • NB 1999–2000 (BP-4W) — Other years in this family inferred from 1999 factory evidence with owner approval; actual-year verification is separate.
  • Verified in: 1999 Mazda MX-5 Miata Workshop Manual
Sources

Also in Additional factory manual gap audit