Periodic stumble

[maestromaestro]

I can't find an answer on the forums, although some people have experienced a similar issue.

The car "stumbles" every so often, not related to the engine temperature (not that I can notice the pattern) and not related to filling the tank. The RPMs suddenly drop to a few hundred, but then it "shakes it off" and there is no other issue.
I can't figure out under what conditions it does it - not very frequently, but it's not a super rare event.

Mine is a 2015 Stage 3 (in Cobb's parlance) - so, charge pipes, intercooler, no cat exhaust, the whole bit (see the lengthy signature...)

Thoughts?

 

[M0LTEN]

My 2015 does the same thing sometimes. not sure why either but I am considering the spark plugs as the first thing to change out.
When my first set of plugs hit 50K it would do the same thing, stumble once in awhile until I put a new set in. its now 18K later and the stumble
is just starting again. I have 68K on the car now. Interested to see if anyone else experiences this and what it turns out to be.
This is not the same issue as putting gas in the car, My car always stumbles/stalls after that but after a couple of miles/minutes it goes away.

 

[maestromaestro]

When my first set of plugs hit 50K it would do the same thing, stumble once in awhile until I put a new set in. its now 18K later and the stumble
is just starting again. I have 68K on the car now. Interested to see if anyone else experiences this and what it turns out to be.
This is not the same issue as putting gas in the car, My car always stumbles/stalls after that but after a couple of miles/minutes it goes away.

We have identical cars... [emoji4]

I am with you on the plugs. 70k on the original set - have just purchased a set of NGK cold gapped by Ron [MENTION=337]whoosh[/MENTION].

Never had the fill up issue that seem to afflict a fair number of people.

 

[Clint Beastwood]

We have identical cars... [emoji4]

I am with you on the plugs. 70k on the original set - have just purchased a set of NGK cold gapped by Ron [MENTION=337]whoosh[/MENTION].

Never had the fill up issue that seem to afflict a fair number of people.

Mine does it with factory plugs, ordered the ngk's from whoosh and it still does it. Seems to coincide with electrical load for me, i.e. if the windows are already up and I hit "up" on both front windows, the rpm's will dip a bit. Maybe it always did it, but its much more noticeable with a RMM and poly mounted exhaust. When my Abarth was doing this, I swapped my 4c coils in to test and it cleared up. A spare set of 4c coils was only 100 bucks believe it or not! Perfect fit and it cleaned up the 500 abarth a lot.

 

[LaserWhisperer]

Mine does it with factory plugs, ordered the ngk's from whoosh and it still does it. Seems to coincide with electrical load for me, i.e. if the windows are already up and I hit "up" on both front windows, the rpm's will dip a bit. Maybe it always did it, but its much more noticeable with a RMM and poly mounted exhaust. When my Abarth was doing this, I swapped my 4c coils in to test and it cleared up. A spare set of 4c coils was only 100 bucks believe it or not! Perfect fit and it cleaned up the 500 abarth a lot.

Alfa 4C???

 

[maestromaestro]

Alfa 4C???

It could be, seeing how they are both made by FCA. Or it is something from a hair care industry.

Having said this, don't hijack the thread, bro.

Sent from my Pixel 3 XL using Tapatalk

 

[LaserWhisperer]

It could be, seeing how they are both made by FCA. Or it is something from a hair care industry.

Having said this, don't hijack the thread, bro.

Sent from my Pixel 3 XL using Tapatalk

Chill out, bro. No one's hijacking anything.
It was only a question, not directed at you either.

 

[LaserWhisperer]

It could be, seeing how they are both made by FCA. Or it is something from a hair care industry.

Having said this, don't hijack the thread, bro.

Sent from my Pixel 3 XL using Tapatalk

Chill out, bro. No one's hijacking anything.
It was only a question, not directed at you either.

 

[maestromaestro]

Chill out, bro. No one's hijacking anything.
It was only a question, not directed at you either.

I AM chill, like a Fonzie.

What you did is the very definition of hijacking a thread. Educate yourself. And seeing how I am the OP, it behooves me to call you on that. A simple "sorry" would have sufficed.

Sent from my Pixel 3 XL using Tapatalk

 

[Clint Beastwood]

Alfa 4C???

Yeah, for roughly 3 months. Not for the tall.

 

[maestromaestro]

So - I still see the rpms drop, but now I think that it MAY be related to fill ups. Additionally, yesterday it cranked for about 10 seconds before firing - right after the fill up (no topping off), but it normally starts immediately.

I did replace the stock sparks with 1 step colder NGKs from @whoosh a few months ago.

Where may all this be heading? I sense there’s an alarming progression here....

 

[PunkST]

Sounds like you have the evap purge valve issues. My car has given me hell with stumbling ever since i put an AP on it ( or so i feel like. Idk im just a sourpuss about it lately)

 

[maestromaestro]

Umm... So, would replacing the valve do anything? It seems that there are some general grumblings around it, but I am not sure if anyone found a definitive solution for the stumbling...

 

[PunkST]

Replacing the valve fixes the problem for a while. Sometimes it comes back. Sometimes it doesnt.

 

[maestromaestro]

Replacing the valve fixes the problem for a while. Sometimes it comes back. Sometimes it doesnt.

Which part specifically - any idea on the part No? There are hundreds with that description that pop up on a Tasca site, for instance.

 

[PunkST]

First i replaced the line under the hood to the intske manifold. Then i replaced the valve and canister under the car ( turns out my canister had a big friggen crack from hitting something last winter.

 

[maestromaestro]

First i replaced the line under the hood to the intske manifold. Then i replaced the valve and canister under the car ( turns out my canister had a big friggen crack from hitting something last winter.

I am dense when it comes to general descriptions. Any chance for the actual part Nos?

 

[PunkST]

D2BZ-9D653-A. Here is the PN for the charcoal canister under the car. ( came with a new purge valve attached) i can look in my pile of papers and such to see the PN for the underhood line. I know i ordered one for a 2014 to be able to use aftermaket intakes easily. Got it from whoosh motorsports.

 

[maestromaestro]

D2BZ-9D653-A. Here is the PN for the charcoal canister under the car. ( came with a new purge valve attached) i can look in my pile of papers and such to see the PN for the underhood line. I know i ordered one for a 2014 to be able to use aftermaket intakes easily. Got it from whoosh motorsports.

Bought on Amazon - today is strange day for me when it comes to buying parts. Everywhere else, it is $115 plus shipping. On Amazon - it is $70.83 and free shipping. Tagged the same and looks the same as everywhere else...

A part number for the underhood line will be very much appreciated... Mine is 2015, so uses a single line... Thanks!

 

[PunkST]

Ron definitely has the right one on his site. But its 129 bucks there. Phone isnt wanting to share the link either. Ill look when i get home. If indidnt throw the box away.