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45k KM, '16 w/ cat back exhaust, RMM, FMIC, turbo smart BOV and WGA, Iridium step colder plugs, tuned by Adam/Tune+. Plugs were purchased from Tune+ and gapped properly.

I've been monitoring the misfire count through the Cobb AP. Before installing the plugs I'd see much more frequent misfires usually when idling or just normal operation, now they occur very occasionally. However, it's always been pretty typical for 3-7 misfires to occur under hard acceleration (either instant peddle mash WOT, or rolling into WOT over about a half a second). This happens only about a third of the time though, usually there's zero misfires. More common in 2nd gear than 3rd.

First, this is bad, right? I'm not being over paranoid, this is a mechanical defect?

If yes, then what/where should I check first? No code has ever been thrown, but when it does misfire under hard acceleration it sucks, seems like the car is hesitating. When it doesn't happen the acceleration and torque is insane.

I'm sorry if there's already similar threads but I haven't read any resolutions for a non-CEL occasional issue like what I'm experiencing.

The car was tuned during the winter and now it's getting warmer, Andy had asked for another batch of logs once it warmed up, how likely is it related to the temperature?



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45k KM, '16 w/ cat back exhaust, RMM, FMIC, turbo smart BOV and WGA, Iridium step colder plugs, tuned by Adam/Tune+. Plugs were purchased from Tune+ and gapped properly.

I've been monitoring the misfire count through the Cobb AP. Before installing the plugs I'd see much more frequent misfires usually when idling or just normal operation, now they occur very occasionally. However, it's always been pretty typical for 3-7 misfires to occur under hard acceleration (either instant peddle mash WOT, or rolling into WOT over about a half a second). This happens only about a third of the time though, usually there's zero misfires. More common in 2nd gear than 3rd.

First, this is bad, right? I'm not being over paranoid, this is a mechanical defect?

If yes, then what/where should I check first? No code has ever been thrown, but when it does misfire under hard acceleration it sucks, seems like the car is hesitating. When it doesn't happen the acceleration and torque is insane.

I'm sorry if there's already similar threads but I haven't read any resolutions for a non-CEL occasional issue like what I'm experiencing.

The car was tuned during the winter and now it's getting warmer, Andy had asked for another batch of logs once it warmed up, how likely is it related to the temperature?



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Check your gap on your plugs.


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45k KM, '16 w/ cat back exhaust, RMM, FMIC, turbo smart BOV and WGA, Iridium step colder plugs, tuned by Adam/Tune+. Plugs were purchased from Tune+ and gapped properly.

I've been monitoring the misfire count through the Cobb AP. Before installing the plugs I'd see much more frequent misfires usually when idling or just normal operation, now they occur very occasionally. However, it's always been pretty typical for 3-7 misfires to occur under hard acceleration (either instant peddle mash WOT, or rolling into WOT over about a half a second). This happens only about a third of the time though, usually there's zero misfires. More common in 2nd gear than 3rd.

First, this is bad, right? I'm not being over paranoid, this is a mechanical defect?

If yes, then what/where should I check first? No code has ever been thrown, but when it does misfire under hard acceleration it sucks, seems like the car is hesitating. When it doesn't happen the acceleration and torque is insane.

I'm sorry if there's already similar threads but I haven't read any resolutions for a non-CEL occasional issue like what I'm experiencing.

The car was tuned during the winter and now it's getting warmer, Andy had asked for another batch of logs once it warmed up, how likely is it related to the temperature?



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The Ford system is quite sophisticated and from what I understand is as follows. Even a totally healthy engine will misfire at times. If the misfire count exceeds a critical threshold that Ford deems unsatisfactory the it throws a CEL. So if no CEL then the misfire count is within whats expected from a healthy engine.
Sometimes you can have too much information and for some people the expectation will be that perfection is the norm. I don't think that's reality. Obviously the less the better but if you're not "feeling" misfires and its not throwing a CEL then I'd say you're good.

Ciao
 

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Discussion Starter #7
I've read those but didn't attribute my misfires to "normal operation" given that I can actually feel the car stutter for that split second.

Are you suggesting this is normal? Do all of ours have that occasional few misfires on hard acceleration that can be felt?

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Possibly like what every buddy else said, sparkplug gap, possibly bad fuel, if you've filled up multiple times, it most likely isnt bad fuel, it could be fuel pressure dip. But if you arent getting a cel, it is most likely a badly gapped plug, dirty, or too cold of plug. The reason why it is most likely that, is the system only sees pre detonation, misfires, and backfires. If the fuel burned but horribly it wont care.
 

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You have the NGKs?
How many miles have they been used?
As others have stated, have you taken the spark plugs out recently after the misfire?
Have you ever put any oil additives in?

Here are the recommendations from tune+ website

0275 for 91/93/E30 and .0245" for E85
 

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Discussion Starter #11
Yeah I've got the ngk's. I bought them pre gaped from tune+ so I didn't even bother to check them. They were installed on Monday brand new. Fuel is Petro Canada 94. Which is what Adam tuned me for. I'll see if I can pull them out and check the gaps.

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The Ford system is quite sophisticated and from what I understand is as follows. Even a totally healthy engine will misfire at times. If the misfire count exceeds a critical threshold that Ford deems unsatisfactory the it throws a CEL. So if no CEL then the misfire count is within whats expected from a healthy engine.
Sometimes you can have too much information and for some people the expectation will be that perfection is the norm. I don't think that's reality. Obviously the less the better but if you're not "feeling" misfires and its not throwing a CEL then I'd say you're good.

Ciao
You'd be surprised. I had a denso plug drop its ceramic over the iridium tip, and it literally misfired at idle, partial throttle, etc. because the ceramic would isolate the gap and prevent ignition from happening. I couldn't get a CEL to pop no matter what I did. Once I pulled the plug and saw that the ceramic was the issue, I replaced it and the misfired went away obviously. Not sure how Ford can let that happen without a CEL, but it happened to me.
 

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You'd be surprised. I had a denso plug drop its ceramic over the iridium tip, and it literally misfired at idle, partial throttle, etc. because the ceramic would isolate the gap and prevent ignition from happening. I couldn't get a CEL to pop no matter what I did. Once I pulled the plug and saw that the ceramic was the issue, I replaced it and the misfired went away obviously. Not sure how Ford can let that happen without a CEL, but it happened to me.
I here you but no system is 100% perfect. As I mentioned in my post its also about what is physically observed. If there is no actual driving symptoms and the OP is going purely on misfire count then I wouldnt worry. The engine like its operating system isnt perfect under all conditions. Modern mechanics also fall for this when you take your car in for an issue you can feel,sense and experience and they look for codes and there isnt any and say there's nothing wrong. Its the combination thats valid in a lot of cases.

Ciao

EDIT......Ok the OP has indicated in a later post he can feel it misfiring as well as the count.
 

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Discussion Starter #14
I here you but no system is 100% perfect. As I mentioned in my post its also about what is physically observed. If there is no actual driving symptoms and the OP is going purely on misfire count then I wouldnt worry. The engine like its operating system isnt perfect under all conditions. Modern mechanics also fall for this when you take your car in for an issue you can feel,sense and experience and they look for codes and there isnt any and say there's nothing wrong. Its the combination thats valid in a lot of cases.

Ciao

EDIT......Ok the OP has indicated in a later post he can feel it misfiring as well as the count.
I definitely notice. It's like the car stutters or hesitates for a a moment before it's starts pulling.

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I've had that split second stutter happen on my completely stock RS once. Was in 4th gear approx 4-5k rpm during a hard pull. Has never happened again, yet. As a side note all I can get here is 91 octane.
 

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If you can only get 91 have you considered water meth? Increases octane and decreased preignition risk significantly


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Sorry, and have you reviewed your logs and checked the ignition timing corrections under load? Are you seeing timing being pulled?


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-"If you can only get 91 have you considered water meth? Increases octane and decreased preignition risk significantly"-

No as Im sure that would void the factory engine warranty. I'm happy with the power with 91 octane. Sorry OP for going a little off topic.
 

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Discussion Starter #19
-"If you can only get 91 have you considered water meth? Increases octane and decreased preignition risk significantly"-

No as Im sure that would void the factory engine warranty. I'm happy with the power with 91 octane. Sorry OP for going a little off topic.
Yolo yo, **** your warranty.

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-"If you can only get 91 have you considered water meth? Increases octane and decreased preignition risk significantly"-

No as Im sure that would void the factory engine warranty. I'm happy with the power with 91 octane. Sorry OP for going a little off topic.
If you tuned your engine warranty is pretty much screwed anyway. If you aren’t then I suppose you could just wait till it windows your block and have ford replace it.

Know which I would rather do. Just saying.


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