TSBs

Replacing Jeep spark plugs

March 18, 2025

This bulletin applies to 2021 Jeep Wrangler and Gladiator vehicles equipped with a 3.6L Pentastar engine.

Related To: Mitchell 1

Replace with P/N SP225755AA. Follow spark plug gaps listed in the service manual.

This bulletin applies to 2021 Jeep Wrangler and Gladiator vehicles equipped with a 3.6L Pentastar engine.

If the engine exhibits rough running and cylinder misfire DTCs are present, the original spark plugs may be cracked internally. Due to a known manufacturing issue with the original spark plugs, all six plugs must be replaced even if only one misfire DTC is present.

Replace with P/N SP225755AA. Follow spark plug gaps listed in the service manual.

About the Author

Mike Mavrigian | Motor Age Editor

Mike Mavrigian has written thousands of automotive technical magazine articles involving a variety of specialties, from engine building to wheel alignment, and has authored more than a dozen books that crisscross the automotive spectrum. Mike operates Birchwood Automotive, an Ohio shop that builds custom engines and performs vintage vehicle restorations. The shop also features a professional photo studio to document projects and to create images for articles and books.