HELP! Do you need to take intake plenum off to swap coil packs?

[steffen707]

When I step on it and get to 5000 rpm I get a random misfire in cylinder #5. Clear the code, it doesn't come back, until I hit 5000 rpms again.

Its past its 3 year warranty with only 27k miles, but dealer wants $540 to replace 1 coil (if that's the issue).

I watched a video on youtube about replacing spark plugs and needing to take the intake plenum off to do so.

But for just swapping the coil on plug, does that need to be done?

Looks like 1 electrical plug and a bolt hold these babies on........

Supposed to drive 7 hours this weekend and want to get it fixed tonight if its that easy.

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[steffen707]

Looks like just a 10mm bolt and a wire plug and these babies are out. Might have to move a line out of the way slightly. Leaving the office for the day to fix this. Fricken $500 to change 1 coil, BAH!

 

[AmishMike]

Plan on an extra 12 hours if you are adding a supercharger while you are in there.

(seems like the right thing to do)

 

[ShadowsPapa]

When I step on it and get to 4500 rpm I get a random misfire in cylinder #5. Clear the code, it doesn't come back, until I hit 4500 rpms again.

Its past its 3 year warranty with only 27k miles, but dealer wants $540 to replace 1 coil (if that's the issue).

I watched a video on youtube about replacing spark plugs and needing to take the intake plenum off to do so.

But for just swapping the coil on plug, does that need to be done?

Looks like 1 electrical plug and a bolt hold these babies on........

Supposed to drive 7 hours this weekend and want to get it fixed tonight if its that easy.

And you have scoped it or otherwise KNOW it's a coil pack? It's not something else? You've run AlfaOBD and captured a freeze frame and it shows misfire ignition?

I guess I'd be concerned about the cost, too, if they are simply throwing parts at it to see if that's the problem.
Left bank, yes. Pull it. (left bank is even)
Right bank (odd numbers) no.
Had to get that done on our 2021 Grand Cherokee as it had a true ignition misfire and it was spark plugs. New plugs fixed it.

I'd ask that they do some diagnosis before spending that sort of money throwing parts at it to see what works.

 

[steffen707]

And you have scoped it or otherwise KNOW it's a coil pack? It's not something else? You've run AlfaOBD and captured a freeze frame and it shows misfire ignition?

I guess I'd be concerned about the cost, too, if they are simply throwing parts at it to see if that's the problem.
Left bank, yes. Pull it. (left bank is even)
Right bank (odd numbers) no.
Had to get that done on our 2021 Grand Cherokee as it had a true ignition misfire and it was spark plugs. New plugs fixed it.

I'd ask that they do some diagnosis before spending that sort of money throwing parts at it to see what works.

Are you saying left bank while you're in the driver seat, or standing at the front bumper looking towards the windshield?

Everything I find says passenger side nearest firewall is number 5.

 

[steffen707]

And you have scoped it or otherwise KNOW it's a coil pack? It's not something else? You've run AlfaOBD and captured a freeze frame and it shows misfire ignition?

I guess I'd be concerned about the cost, too, if they are simply throwing parts at it to see if that's the problem.
Left bank, yes. Pull it. (left bank is even)
Right bank (odd numbers) no.
Had to get that done on our 2021 Grand Cherokee as it had a true ignition misfire and it was spark plugs. New plugs fixed it.

I'd ask that they do some diagnosis before spending that sort of money throwing parts at it to see what works.

Unfortunately I haven't scoped it, assuming you mean oscilicope?

I thought cylinder 5 was passenger side closest to firewall.

I swapped coil packs with cylinder 3, misfire continues on cyl 5. Changed plug in cyl 5,issue still happens.

So either cylinder 5 is elsewhere, it's a bigger problem than coil pack and plug, or the Mopar sparkpkug I installed is also bad and misfires above 5,000rpm

 

[Charles 236]

Unfortunately I haven't scoped it, assuming you mean oscilicope?

I thought cylinder 5 was passenger side closest to firewall.

I swapped coil packs with cylinder 3, misfire continues on cyl 5. Changed plug in cyl 5,issue still happens.

So either cylinder 5 is elsewhere, it's a bigger problem than coil pack and plug, or the Mopar sparkpkug I installed is also bad and misfires above 5,000rpm

Cylinder #5 is on the passenger side closest to the firewall. If you have already swapped the #5 coil and plug to other cylinders and still get a cylinder #5 misfire, you have some other issues. A high RPM misfire could also be caused by an intake rocker arm not switching between low lift and high lift at the correct times. It could be a intake camshaft failure, but normally you will have some noise calling attention to the valvetrain.

Another possibility is a fuel injector, but injector failure is rare. If you do go to the dealership, ask for the tech to perform a VVL Service Test, this will give a great starting point for further diagnosis if it doesn't show the issue outright. I always tell our techs to run this test if the coil, spark plug and injector dance doesn't give a clear direction to go.

 

[dmwphoto]

Are you revving to 5000 rpms with a load or no load?

 

[Lost1wing]

Isn't a misfire considered part of the powertrain warranty? How long is the powertrain warranty? I'm just asking for a friend.

 

[steffen707]

Are you revving to 5000 rpms with a load or no load?

like if I was pulling into the highway to get up to 70. You can't Rev past 3000 in neutral.

 

[steffen707]

Isn't a misfire considered part of the powertrain warranty? How long is the powertrain warranty? I'm just asking for a friend.

The dealership said if it's bolted to the engine it's only part of the 3/36000 mile warranty, but if it were a rocker arm, then maybe it should be powertrain 5/60000 I believe.

 

[steffen707]

Cylinder #5 is on the passenger side closest to the firewall. If you have already swapped the #5 coil and plug to other cylinders and still get a cylinder #5 misfire, you have some other issues. A high RPM misfire could also be caused by an intake rocker arm not switching between low lift and high lift at the correct times. It could be a intake camshaft failure, but normally you will have some noise calling attention to the valvetrain.

Another possibility is a fuel injector, but injector failure is rare. If you do go to the dealership, ask for the tech to perform a VVL Service Test, this will give a great starting point for further diagnosis if it doesn't show the issue outright. I always tell our techs to run this test if the coil, spark plug and injector dance doesn't give a clear direction to go.

Wow, thank you very much! I'll stop by the dealership tomorrow. I'm actually rooting for a camshaft, valvetrain, or injector issue. I think those are all part of the powertrain warranty.

I was told if it was just coil or plug, that wouldn't be part of the powertrain. Is that right?

 

[SteveInOrlando]

you are stating misfire, are you getting P0300 engine code? you are the correct milage for it to potentially be early lifter Cam lobe issues. For some reason the right bank always goes before the left bank.

 

[steffen707]

you are stating misfire, are you getting P0300 engine code? you are the correct milage for it to potentially be early lifter Cam lobe issues. For some reason the right bank always goes before the left bank.

I don't know what the code was, the service guys just said misfire on cyl 5. I could ask them to check. Is P0300 linked to this early lifter cam lobe issue?

 

[Hootbro]

The dealership said if it's bolted to the engine it's only part of the 3/36000 mile warranty, but if it were a rocker arm, then maybe it should be powertrain 5/60000 I believe.

Your dealership is right. I had to double check the powertrain warranty language and it is basically just the internal mechanical parts. Nothing is mentioned about covering the electronics.

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