Pentastar Misfire

[guidefreitas]

Hi! My Gladiator has around 10k miles and it started presenting misfires. I tryed a few shops and a local dealership without success. I'm from Brazil and Gladiators are pretty rare here. - Jscan logs attached.

Conditions:
- Misfires intensify after ~30min drive
- They seems to happen ~2000rpm at normal cruising ~60mph
- They are more intense on cilinders 2, 4 and 6 but also happend on 1, 3 and 5. So both banks are impacted.
- The misfire stops when in traffic

Things I've already done:
- Change spark plugs
- Clean and test the fuel injectors
- Change fuel to 93 octane (25% ethanol) - No change
- There's no obvious air leak

Any ideas are appreciated! Thank you.

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[Pickle_Bill]

25% ethanol is too high. 15% max I believe. Most fuel here in the US is 10%.

 

[guidefreitas]

Accordingly with the dealership, officially imported Jeep Gladiators have a special tunning to handle Brazil gas (up to 30% ethanol), so it should be fine.

Other things I found out and changed this week
- Alternator pulley shaft changed. It had a small wiggle.
- Main and secondary batteries changed. They had a voltage drop.
- Main crankshaft sensor verified: no problems there

None of that solved the misfires, as expected, but at least they are out of the equation now.

I'll keep posting the updates here, hopefully it will be useful for someone else.

 

[BRMoose]

Swap coil pack between cylinders and see if the misfire follows

 

[guidefreitas]

We swapped a all the coils from a healthy gladiator to test, the problem persisted. Thank you for the tip, though.

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