put all fresh plugs in

What brand/model and what was the source (retailer) of those plugs? I'd start with a new spark plug on cylinder 1 and moving the coil from cylinder 1 to another cylinder (one on the front bank). That's starting with the cheapest option first.

The cylinder doesn't get damaged with VCM, it just carbons up and sticks the rings in a bad orientation. Don't lose hope yet.

-Charlie

 

I believe they were NGK plugs from AutoZone? I looked up whatever the OEM was and probably matched it.

Good to know the cylinder likely isn't damaged! I'll give that a try.

Thanks!

 

Also. At about 150K, its time for a valve adjustment. VCM is NOT the only thing that can cause misfires. Its just ONE of the things that can and is very common. You are ahead of the pack being muzzled and all.

In addition to VCM, a bad plug, a bad coil, a bad injector or too loose or tight valves can cause misfires. I would start with swapping the plug to a different cylinder. Then the coil if the misfire does not move and so on. Several threads on how to troublshoot misfires are on here.

Finally, at 150K ish, its time for a valve adjustment and valve cover gasket work any way so get that done as well.

Just yesterday, there was a thread of a bad injector on a 8xK mile 2016 so anything is possible.

 

Misfires can be caused by so many things. You need to determine the cause of it first before jumping to conclusions.

 

Good advice above. Also, it may be worth doing a piston soak to clear up the rings a little faster.

 

Start by taking out the spark plug and checking the condition. If it's clean, swap plugs 1 and 2 and see if the error follows. If it's still on 1, try swapping coils. Go from there.

 

This ^^^
The condition of the replaced plug, is your clue to whats going on in that cylinder.

oily mess vcm, dry... likely injector, coil, pcm issue or worse, a burned valve.

 

I would not rule out injector balance. Would have to look at fuel rails to say how likely, but have twice seen and fixed cars where dead-end rails, end position made one silt up way early. Homebuilt injector tester showed large delivery imbalance. I bought a set of used ones off the internet and reinstalled the closest grouped 8 of the 16. Not a Honda, obviously - a Lincoln and a Porsche. But 2 for 2 on this being an eventual problem for every EFI motor that doesn't "sweep through" the rails.

When I put the aftermarket intake on my Camaro I made the feed, Y-blocked to feed both and another Y-block to relieve both, so any silt got another chance at the filter.

 

Homebuilt injector tester showed large delivery imbalance.

For those that don't want to build their own tester, there are a ton of options for testing and cleaning services - but you have to be ok with the vehicle being down for a bit for shipping, etc. Generally a better (and cheaper!) option than getting new injectors - that are either crazy expensive (dealer) or questionable quality (Amazon, eBay, etc.)

-Charlie

 

Yeah, I built that tester back when I had no choice,
there were no forums like this. Later on I just paid
guys to clean and flow-test, for about what I paid
for the boneyard fuel pump, regulator and rails
I used to make the tester (along with a graduated
cylinder and a timed pulse train generator to drive
the injector).

But vs shop rates? Fuggedaboudit.