[javid19]

Cylinder 3 misfired 1 month ago, all spark plugs were changed and car has been running fine. However, in the past two days my engine has misfired twice on the same cylinder 3. Is it more likely due to ignition coils or vcm?

 

[Miker]

How many miles? maintenance routine? driving habits? Hwy or city?

What did cyl 3 plug specifically look like as well as the other plugs?

A weak, leaky or plugged fuel injector(s) also cause misfires.

Are the misfires occurring at idle, WOT, or typically at one RPM or another? Engine "cold" or warmed up or both?

Do the coil pack dance routine and see if the misfire follows the coil.

 

[javid19]

The car is at 130,000 miles, regularly maintenance. The misfire occured at steady speed. Rough idling afterwards. The engine was warm. Regular driving habits, don’t accelerate harshly, speed or slam brakes often.

 

[Miker]

Steady speed, warm engine with rough idle tends to make me think fuel injector.

Under that scenario you are not asking for lots of fuel as opposed to say WOT, cold engine at first start, etc.

I'd still swap coils to verify it's NOT the coil.

As far as VCM I believe I am correct that cyl 3 typically is the one that is always operation when it does the 6-4-3 deactivation so it may just be weak. That's a guess though until we know for sure if it truly operates in that manner.

 

[WiiMaster]

As far as VCM I believe I am correct that cyl 3 typically is the one that is always operation when it does the 6-4-3 deactivation so it may just be weak. That's a guess though until we know for sure if it truly operates in that manner.

Cylinder 3 is the cylinder that gets deactivated the most, as it is deactivated in both the 4 and 3 cylinder modes.

So OP, do you have a V6 since you reference VCM? Disabling VCM would be a good start.

 

[20AccordEXL11]

Title of the thread says 3.5 liter so I'd guess he does have a V-6.

Short of changing the coils to see if the miss follows it, it may just be some carbon buildup coming loose and temporarily causing the plug to miss fire.
An Italian tune-up would not be out of the realm of fixes, IMO.
Cheap, fun, and it might just fix it too.

 

[stiller fan]

Cylinder 3 misfired 1 month ago, all spark plugs were changed and car has been running fine. However, in the past two days my engine has misfired twice on the same cylinder 3. Is it more likely due to ignition coils or vcm?

Do you burn oil? Cylinder 3 with VCM tends to foul that plug. Had that issue on a delivery a couple years ago in friends wife pilot.

 

[Miker]

Cylinder 3 is the cylinder that gets deactivated the most, as it is deactivated in both the 4 and 3 cylinder modes.

Less use confounds the problem and probably leaves that cyl 3 injector suspect.
EDIT:
@javid19 I'd still like to know what that plug looked like when you replaced them. If it was all goobered with blowby oil from the mostly deactivated cylinder, it may be doing it again.
Are you losing oil to any extent?

 

[WiiMaster]

Less use confounds the problem and probably leaves that cyl 3 injector suspect.

The cylinder that gets deactivated the most is the one that is going to have the most issues. I seriously doubt this is an injector problem. It sounds like a very typical case of plug fouling from VCM activation.

 

[Bruce Hawkins]

Swapped the #3 spark coil for the #1 - See if the misfire suddenly happens on the #1.