HELP P0354 Cylinder 4 Misfire

[isaiah990]

I have a 2013 FR-S, right side of engine near cylinder 4 engine shakes and rattles ECU is throwing P0354 and P0304
Engine is also making a weird noise near the right side of engine
-I've replaced ignition coils and spark plugs on cylinder 4 with no luck, any ideas what it could be?
I've noticed the coil pack does not sit completely flush when plugged on, is it supposed to sit tight and flush against the engine/spark plug?

[isaiah990]

Here is a video of my car
[ame]https://www.youtube.com/watch?v=6nL6xUVrzRU[/ame]

[humfrz]

Originally Posted by isaiah990

I have a 2013 FR-S, right side of engine near cylinder 4 engine shakes and rattles ECU is throwing P0354 and P0304
Engine is also making a weird noise near the right side of engine
-I've replaced ignition coils and spark plugs on cylinder 4 with no luck, any ideas what it could be?
I've noticed the coil pack does not sit completely flush when plugged on, is it supposed to sit tight and flush against the engine/spark plug?

Hello isaiah990 and welcome to our forum -

Happy holidays!

So, your car is acting up. Do you have any power mods?

You replaced the #4 plug and coil.

I reckon the coil should fit snug onto the spark plug. Is it fitting differently than the other coils? You might try swapping a couple of the coils to see if the engine code changes.

After that, I'd suggest you disconnect the battery for a spell, hook it back up and see if any codes come back.

The next easiest thing to check would be to check for a vacuum leak.

I hope you get it sorted out.


humfrz

[JD001]

Originally Posted by humfrz

Hello isaiah990 and welcome to our forum -

Happy holidays!

So, your car is acting up. Do you have any power mods?

You replaced the #4 plug and coil.

I reckon the coil should fit snug onto the spark plug. Is it fitting differently than the other coils? You might try swapping a couple of the coils to see if the engine code changes.

After that, I'd suggest you disconnect the battery for a spell, hook it back up and see if any codes come back.

The next easiest thing to check would be to check for a vacuum leak.

I hope you get it sorted out.


humfrz

You feeling okay? I thought diesels sound like that.. get a petrol if wanting something a bit more civilized..

Happy holiday.. BTW, I bet the sand helped with the digestion.... A bit of grit is good for the gut...

[humfrz]

Originally Posted by JD001

You feeling okay? I thought diesels sound like that.. get a petrol if wanting something a bit more civilized..

Happy holiday.. BTW, I bet the sand helped with the digestion.... A bit of grit is good for the gut...

Oh, I get it, the OP took a video of his engine, then dubbed in the sound track from a running, old, Bulgarian, diesel tractor engine -

A bit of sand is good for the turkey's gut -


humfrz

[Opie]

If coil is not sitting flush, something is wrong. Either the plug isn't installed properly or fully, or the coil has an issue.

Where did you get the new plug and coil?

Once those issues are corrected if the code(s) persist it may be an issue with the engine harness. Subaru has a TSB regarding this.

[isaiah990]

Thanks for your response I’ve swapped coils and I’ve also replaced them. Spark plugs have been replaced already so maybe wiring harness or something else?
I got the spark plug from the Toyota dealership and the coil pack from autozone

[isaiah990]

Any ideas what that noise could be? I couldn’t find any other videos with a similar noise

[isaiah990]

The noise seems to come in low idle after about 15 seconds of my car warming up

[tomm.brz]

Originally Posted by isaiah990

The noise seems to come in low idle after about 15 seconds of my car warming up

after 15 more or less seconds the only things that can change are:
-direct injectors goes on and port injector goes off
-oil circulates into the AVCS and activates it

[isaiah990]

Originally Posted by tomm.brz

after 15 more or less seconds the only things that can change are:
-direct injectors goes on and port injector goes off
-oil circulates into the AVCS and activates it

Thanks for your reply, I was thinking it could be the injectors, would that cause a code p0354 or somehow affect the coil pack? I’ve unplugged the cylinder 4 coil pack ignition D while the car was running but it did not change anything so I’m not sure if it’s the coil pack or injectors causing it. I’m trying to get this fixed asap hopefully before New Years but I’m having trouble diagnosing the problem

[isaiah990]

UPDATE: coil pack or wiring harness to do not seem to be the problem. Noise only comes on after engine warms up about 15 seconds. I’m assuming it could be the injector responsible for cylinder 4.

[Stomachbuzz]

Originally Posted by tomm.brz

after 15 more or less seconds the only things that can change are:
-direct injectors goes on and port injector goes off
-oil circulates into the AVCS and activates it

I disagree. As far as I know, there are several events that take place when a motor is cold that change/stop happening later on.

As you said, at some point, the injection method switches, and the 'crickets' can be heard.
Not sure about the AVCS as I'm not familiar with that.

Modern cars also have a secondary air injection (kinda sounds like a jet engine, but not as loud unless your air pump is going bad) for about ~90 seconds when a car is cold.
There are a few other processes that change as well, and you can clearly hear the idle change sound and speed throughout the process.

Originally Posted by isaiah990

Thanks for your reply, I was thinking it could be the injectors, would that cause a code p0354 or somehow affect the coil pack? I’ve unplugged the cylinder 4 coil pack ignition D while the car was running but it did not change anything so I’m not sure if it’s the coil pack or injectors causing it. I’m trying to get this fixed asap hopefully before New Years but I’m having trouble diagnosing the problem

Yes, I can hear the miss. This type of engine should not have an idle that is so choppy.
I am also concerned about that metal rapping sound. It's an accessory, I'm sure, but still distracting in the video. These types of sounds never show up well in video recordings.

The why you start diagnosis with ignition problems is to start switching the coils around.

Computer says cyl#4 misfire?
Swap cyl#1 ignition coil with cyl#4 ignition coil and see if the code follows over to cyl#1 or stays at #4.

Obviously, this is assuming that the coils are properly installed, and there isn't a glaring issue such as debris in the spark plug hole (maybe why your ign coil isn't seating properly?) or other.

[isaiah990]

Originally Posted by Stomachbuzz

I disagree. As far as I know, there are several events that take place when a motor is cold that change/stop happening later on.

As you said, at some point, the injection method switches, and the 'crickets' can be heard.
Not sure about the AVCS as I'm not familiar with that.

Modern cars also have a secondary air injection (kinda sounds like a jet engine, but not as loud unless your air pump is going bad) for about ~90 seconds when a car is cold.
There are a few other processes that change as well, and you can clearly hear the idle change sound and speed throughout the process.



Yes, I can hear the miss. This type of engine should not have an idle that is so choppy.
I am also concerned about that metal rapping sound. It's an accessory, I'm sure, but still distracting in the video. These types of sounds never show up well in video recordings.

The why you start diagnosis with ignition problems is to start switching the coils around.

Computer says cyl#4 misfire?
Swap cyl#1 ignition coil with cyl#4 ignition coil and see if the code follows over to cyl#1 or stays at #4.

Obviously, this is assuming that the coils are properly installed, and there isn't a glaring issue such as debris in the spark plug hole (maybe why your ign coil isn't seating properly?) or other.

The metal rapping sound is what I’m trying to figure out, I thought it was part of the misfire
-I’ve swapped coil packs and the misfire remains on cylinder 4
-cylinder misfire occurs constantly after 15 seconds when idle rpm drops on cold start
-When I unplug coil pack #4 right after I start the car it causes it to stall. When I unplug the same coil pack after the misfire occurs or 15 seconds after start it has no effect on the idle
Could this noise be a failing injector?
Here is another clip right after start up. I have UEL headers and N1 catback