need plug advice

[threeunderpar]

So coming home on a long road trip the engine light came on and immediately felt rough and like a misfire was happening. I run JB4 and got a P0306 code. I took off the JB4 temporarily to see what would happen and the light went away. A few hundred highway miles later the light came on under acceleration but it didnt run rough like before. I'm home now and reinstalled the JB4 and have the P0306 code. I have Densos plugs installed since 18k miles and am at 33k now. My question is should I replace #6 only or do them all again? How long are your Densos lasting you?

 

[MerlintheMad]

The JB4 complicates things maybe, but my limited experience with this CEL and rough running pointed me to checking the boot/coil pack unit: I kept losing the no. 6 cylinder sparkplug and it was the boot/coil pack unit that was bad and killing plugs. Replaced that along with the cracked plug and it's been running well since the end of March. In my case, I would only get a CEL and rough running under boost acceleration: if I drove like a sane, calm grandpa and kept the turbos out of it, the car felt fine.

 

[StingertimeNC]

I would replace them all. You got 15k out of them. If they did that well, I wouldn't hesitate to go Denso again, just get them from somewhere reputable, like Burger Motorsports or something. Of course you could always go HKS. Merlin may have a point about the coil being bad though, but with the JB4 and running Denso's for 15k miles it may be worth a shot to just start with the plugs.

 

[oddball]

My Densos only lasted ~18k miles, so they may just be dead.

 

[Aarvix]

15K is par for the course with Densos and JB4.

HKS will last longer, but cost more.

 

[G70LEbyAdoom]

Get some HKS plugs and swap them all. The Densos are good, but the HKS seems to be more reliable from the general consensus on the forum.

 

[threeunderpar]

I swapped out the plugs of 6 and 4 and still got a code for 6. Might very well be the coil/boot on 6. Are those easy to obtain these days?

 

[Rodtheviking]

eBay is your best bet for coils right now.

3.3L 3.8L Ignition Coil ⭐GENUINE⭐ for Sedona Stinger Sorento Cadenza 2018-2020 | eBay

If there is any factor that you were not.

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