Showing specs for all NA & NB Miatas

Spark plug gap (NB2)

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 2001–2005 (BP-Z3) — Other years in this family inferred from 2005 factory evidence with owner approval; actual-year verification is separate.
  • Verified in: 2005 Mazda MX-5 Miata Workshop Manual (electronic manual capture)
Sources
  • 2005 Mazda MX-5 Miata Workshop Manual (electronic manual capture)Tier 1
    Page PDF p. 914
    Printed: “Plug gap 1.0—1.1 mm {0.040—0.043 in}”

Also in Additional factory manual gap audit