P0307 2014 Suburban

[MN-cj]

On way to work at stop sign and stop light, I noticed the tachometer "bobble" a little at idle. It has had ever so so slight done that since I got it in 2014 and stealership said it was normal. It was a little more than that this time I thought but it went away and no light came on. After work, I remote started it and it was not running when I came out. Started it & the check engine light came on blinking and it had turned off the stability track and traction control plus running like it was missing. I put my OBDII reader in and pulled up TorquePro to see the code which it stated cylinder 7 misfire (P0307). Truck has 227k miles on it.

1. Assuming I need to replace plug wires and plugs? (OEM original I hate to say)
2. Also assuming from research ACDelco 748UU and ACDelco 41-110 plugs are way to go?
3. Assuming I don't need to replace the coils, correct?

Thanks in advance for the advice.

 

[Marky Dissod]

... 227k miles on it.

1. Assuming I need to replace plug wires and plugs? (OEM original I hate to say)
2. Also assuming from research ACDelco 748UU and ACDelco 41-110 plugs are way to go?
3. Assuming I don't need to replace the coils, correct?

1. Ten years, 227k miles, original plugs and wires ... YES ... time to change them, finally.
2. If those are compatible with what's called for, should be fine (unless you want to upgrade for some reason ...).
3. Being a pessimist, I'd relocate the 7th coil to a different cylinder. If the misfire follows that coil, replace that coil sooner.
Then buy at least seven more coils now (while they're cheaper) to replace later.

 

[MN-cj]

Thanks Marky. Moving 7 up to 1 or 3 would make it a little easier to get to and verify if it is the problem. Are you suggesting the price of coils are going to go up?

Looking on AutoZone just now, I assume figure out if I have the square or round coil and then buy ACDelco D510C or D514A respectively?

 

[Marky Dissod]

Are you suggesting the price of coils are going to go up?

Has anyone ever suggested the price of anything going DOWN?
I'd actually suggest that you buy whichever coil the hotrodders prefer.
They usually know which ignition components live with enthusiasm better, if there is such a thing.

 

[Fless]

Isn't cylinder #7 an AFM cylinder?

 

[Marky Dissod]

Cylinders 1, 4, 6, & 7 are the lazier ones, yes.

 

[wjburken]

I would simply begin with changing plugs and wires. If that doesn’t take care of it, then swap coils.

#7 seems to takes the brunt of any oil that gets sucked into the intake from the PCV hose from the DS valve cover so tends to foul sooner than the others.

 

[Marky Dissod]

#7 seems to takes the brunt of any oil that gets sucked into the intake from the PCV hose from the DS valve cover, so #7 tends to foul sooner than the others.

Besides disabling / deactivating V4 mode is there anything ELSE that can be done to make #7 less likely to suck?

 

[Fless]

Besides disabling / deactivating V4 mode is there anything ELSE that can be done to make #7 less likely to suck?

Updated driver's side valve cover. Catch can.

 

[wjburken]

Besides disabling / deactivating V4 mode is there anything ELSE that can be done to make #7 less likely to suck?

Put a catch can in.

#7 is an issue independent of AFM.

Since this is on a 2014, I’m assuming it already has the newer valve cover design from the factory that is supposed to reduce the amount of oil that’s sucked into the intake.