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When are misfires a cause for concern?

blaqsheep

blaqsheep

Autocross Champion
Location
Canada
Car(s)
IS38 GTI
I've got a 2018 GTI and have experienced my fair share of misfires, most of them during colder days or idling at a light. I feel the lumpy misfires pretty consistently. Now I'm not sure if I felt these as noticeably prior to having a downpipe, but now I am running a downpipe and JB4.

I did some reading on here and it seems that it is relatively normal as the engine is trying to be efficient and this causes slight misfires at idle. Some people have resorted to getting new coil packs and spark plugs.

So my question is, when do these misfires start becoming a cause for concern? Is there something I should be logging other than general VCDS faults to make sure what I'm experiencing is normal.
 
blaqsheep

blaqsheep

Autocross Champion
Location
Canada
Car(s)
IS38 GTI
I wonder if it's because of the downpipe I'm feeling it more. It is also leaking so that can't be helping lol.

So basically check logs to make sure I am getting no misfires under load. Is there anything one can do to smooth out the misfires? One step colder plugs? Or just don't fix it if it ain't broken.
 
G

GroceryGTIer

Drag Racing Champion
Location
Tri-state
blaqsheep said:
I wonder if it's because of the downpipe I'm feeling it more. It is also leaking so that can't be helping lol.

So basically check logs to make sure I am getting no misfires under load. Is there anything one can do to smooth out the misfires? One step colder plugs? Or just don't fix it if it ain't broken.
Click to expand...

An exhaust leak can cause a rich condition, so be careful, keep an eye on your mileage.
 
blaqsheep

blaqsheep

Autocross Champion
Location
Canada
Car(s)
IS38 GTI
Getting a cat welded in and will have them take a look at the slip joint, I didn't see any soot from under but it appears to be some when looking from the engine, even with the upgraded clamp. The midpipe to factory exhaust is 100% leaking.
 
blaqsheep

blaqsheep

Autocross Champion
Location
Canada
Car(s)
IS38 GTI
No fault codes so far. Ran the VCDS misfire counter idling on a warm engine on map 2 and got 13 misfires on cylinder 2.

Switched to map 0 and watched it run with 1 or 2 misfires then reset and it didn’t count anything. Set back to Map 2 and watched while idling, no misfires. Strange that it’s only cylinder 2.

Right after I filled gas I could feel it misfiring like nuts while idling at the gas station.


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Hambone

Hambone

Go Kart Newbie
Location
Florida
Car(s)
2020 TR GTI SE
blaqsheep said:
So is this normal? Do I need new plugs?
Click to expand...

I had a misfire issue where I was actually throwing codes for intermittent/random misfires on Cylinder 2 and 3. Have yet to pop an EPC/CEL or really feel them at anything other than idle. The EA888 Gen3 is known to 'fishbite' while idle/very low speeds, which is what is tripping your misfire sensor.

I replaced my plugs with Brisk Silvers and went with RS3 coilpacks, and only get stored codes once in a great while, but feel absolutely nothing wrong with the engine. If you are not tuned and have a warranty, and are concerned, take it to your service department to see if they can dig anything up. Otherwise I'd suggest you make sure you're running a quality 93 octane fuel and monitor it. As others have said, if you aren't getting misfires under load, its generally not something to be overly concerned about. Be concerned if you misfire under load.
 
gtibrad

gtibrad

ZUM DIS
Location
FO
Sounds to me the fuel may be causing it...but could've read too quickly above.

It is normal to see misfires picked up by the misfire counter without storing a code. When it stores a code...then worry. If wanting to try a few things...remove the #2 plug and inspect or even take a pic and post it. Clean the threads for the plug both in the head and on the plug to improve its ground/earth before reinstalling it. Try disconnecting the #2 coil at the harness and spray both connections of the harness and coil with electrical cleaner and reattach. Try a new #2 coil...if it doesn't help, you'll have a spare for when needed. I doubt a colder plug will help if happening at idle or low revs and would only be concerned about heat if were happening when hot. No point giving it a plug that cools faster when doing this at low revs alone.


Best plugs I have found to date are NGK PFR7B...but really will help when you have high rev misfires and need a colder plug.
 
Last edited:
bruxwillix

bruxwillix

Ready to race!
Diggs24 said:
Normal. If you get them under load then be concerned.
Click to expand...
do the normal ones show up on obdeleven and do the normal ones occur in every cylinder? i keep gettin intermittent misfire codes on cyl 1 and 2. cleared and got em again. plugs are at 3k and was gonna change packs but also how serious are intermittent misfires? TIA

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CaptainRatty

CaptainRatty

Autocross Champion
Location
Winston-Salem, NC
Car(s)
MK7 GTI
I'll chime in with my anecdotal observations.... 27k miles on the car and have been stage 2 since 24k miles. I logged misfire sum counter and number of misfires for all cylinders on a 200 mile drive the other day. Cylinders 1&4 had none and 2&3 had 2 each. Like OP, I too am curious if this is a cause for concern. I'm thinking not considering no cel whatsoever.... The only way I would have ever known is because I logged with OBDEleven. I've seen the logs and videos online of real misfire issues and the numbers I'm seeing are much much higher (dozens of misfires per cylinder). I'm still on the stock plugs after speaking with my indy shop and Unitronic... They recommending just replacing them with another set of stock plugs at 40k.
 
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