Mopar SP149125AF is the current OEM spark plug for the JK's 3.6 Pentastar. It's the same plug as Champion 9407 (type RER8ZWYCB4). The job itself isn't hard, but the rear plugs on the driver bank require pulling the upper intake, which is why people want to buy the right plug once.
Fitment
2012–2017 Wrangler and 2018 Wrangler JK, 3.6 Pentastar. The 2007–2011 3.8 uses a different plug (Champion RE14PLP5). Always confirm the number on your old part or run your VIN at a Mopar parts counter before you order.
Common failure symptoms
- Misfire codes (P0300–P0306) or a rough idle
- Hesitation under load or on the highway
- Plugs are due at the maintenance interval in your owner's manual
- Worn plugs found while you have the intake off for the oil cooler housing
Cross-reference
| Brand | Part number | Notes | Source |
|---|---|---|---|
| Mopar | SP149125AF | Current. Supersedes SP149125AD and AE. | source |
| Champion | 9407 / RER8ZWYCB4 | Same plug as the Mopar number. Buy six. | source |
Rebuild, repair or replace?
Plugs are replaced, never cleaned and reused. Buy six of the same number. The 2014 JK owner's manual prints a gap of 0.043 in (1.1 mm). Torque the plugs to 13 ft-lbs, which is low enough that a careful hand and a proper wrench matter. If you're already pulling the upper intake to reach the rear plugs, inspect the oil cooler housing in the valley at the same time. That combined job saves a second teardown.
Where to buy
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FAQ
Is Champion 9407 the same as Mopar SP149125AF?
Yes. The Champion interchange lists the Jeep/Chrysler SP149125 numbers.
Can I use this plug in a JL?
No. The JL 3.6 uses Champion 9417 / Mopar SP225755AB.
What gap and torque?
0.043 in (1.1 mm) gap and 13 ft-lbs, per the guide.
Related guides
Sources
Part numbers and fitment were checked against the sources above on October 22, 2026. Mopar supersedes numbers over time. If a newer letter suffix shows up, it generally replaces the one listed here. Back to the parts lookup.