Author Topic: 15 STI Idle & stall Issue / Cylinder 1 misfire  (Read 2617 times)

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Offline 3inchesoflove

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15 STI Idle & stall Issue / Cylinder 1 misfire
« on: May 31, 2016, 10:31:01 am »
Sitting at 75,000km on my 2015 STI, stock, and starting to get some low rpm issues.

For the last couple months, it has been idling rough ( worse when cold/just after start up) and has gotten to the point it will stall when I clutch in at a red light. I have to keep my foot on the throttle to ensure RPMs stay above 1000, any time they drop under I get a really rough idle and a chance it will stall.

I assume it is related, but I have been getting Cylinder 1 misfires once every couple of weeks, generally in the same conditions cool/just started engine at low rpms.


Any suggestions? I am going to start the mind numbing process of contacting the dealer, but I can guarantee without a CEL they will not do a thing.

Offline cha0tik

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #1 on: May 31, 2016, 02:51:29 pm »
Difficult to tell without pulling a code, but have you checked your oil level recently?
A few things these engines are prone to are the oil pickup tube cracking as well as the infamous ringland issue.
Also, misfire in a cylinder could be due to a bad spark plug. A buddy recently had a similar issue and it turned out he needed new spark plugs.

If you can, try to have the dealer do a compression and leakdown test on the engine. At least then you can rule out the internals themselves.
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Offline jakesubie

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #2 on: May 31, 2016, 06:22:36 pm »
 Id swap out the spark plugs and go from there

Offline Rad_Racer

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #3 on: June 03, 2016, 11:42:11 am »
Are you running Cobb AP for your protune? Is your DAM consistently at 1.000 or is it reduced? FKL/FK values?

Agree with checking spark plugs.

Offline 3inchesoflove

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #4 on: July 05, 2016, 03:19:08 pm »
Update:   First time the dealer looked at it they swapped coils around and said something about an oil valve they swapped around as well?  Not sure about the oil valve or what it was actually called, as I don't remember.   

Either way, issue went away for all of 2 hours then the check engine and rough idle were back.

Took it in a second time this week and just got the call, no compression in cylinder 1&3 i believe, so they are starting the warranty work to fix.  Have no idea how far the fix is going to go, they just asked me to submit all my oil change paperwork.

I will update again when I hear more. 

Offline Stealthbombing

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #5 on: July 05, 2016, 03:27:49 pm »
After 8 years you would think that they fixed this problem, i dont understand.

Good luck man, if you have your oil change receipts you should be in the clear for a new engine.
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Offline jakesubie

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #6 on: July 05, 2016, 03:32:59 pm »
Tbh if you have warranty and have done all the required maintenance drive the isspay out of it. Still a itshay situation

Offline SingallZ

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #7 on: July 06, 2016, 12:18:24 am »
If you don't mind me asking where are you getting the "warranty work" done? I've heard of others blowing rings in the past with no "oil change documentation" required.

Also good luck with it, nothing worse than a blown motor (or transmission)

Offline 3inchesoflove

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #8 on: July 06, 2016, 10:18:15 am »
Its all getting done at Centaur Subaru... and I have got to be honest, so far it has been completely painless.   I totally get them asking for the oil change documentation, as I had only done two services with them.   Only downside is they do not provide a vehicle to drive in the meantime, and I am going to be out for a couple weeks.   

Offline cha0tik

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #9 on: July 06, 2016, 09:13:53 pm »
Its all getting done at Centaur Subaru... and I have got to be honest, so far it has been completely painless.   I totally get them asking for the oil change documentation, as I had only done two services with them.   Only downside is they do not provide a vehicle to drive in the meantime, and I am going to be out for a couple weeks.

Can you get your insurance to provide you with one, or would this be stretching it?
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Offline toytech

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #10 on: July 07, 2016, 10:22:48 pm »
Seriously ? Get them to rent you a car , warranty will cover a rental if no loner is available . They cant expect you to walk for a couple of weeks . Talk to a manager and give them crap , dealers can do better than that .

Offline coop3422

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #11 on: July 09, 2016, 03:46:05 pm »
A 2015 with 75k, wow you drive a lot haha. Glad to hear the warranty process has been pretty painless so far though!

Offline 3inchesoflove

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #12 on: July 20, 2016, 10:38:46 am »
So the subaru mechanics are telling me it was the valve seats that failed in cylinder 1 & 3.   So they are getting the heads machined and rebuilding the engine for me. 

So far it has been pretty painless other than the fact they have had my car for 3 weeks and don't offer a loaner, I would have been choked about this but just got a new Street Triple R, so despite the fact I have been pretty wet the last couple weeks, my motoring life has been great. Here is hoping the built engine is better than the original, sounds like the perfect time to go stage 2.   

Offline funk32

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #13 on: July 20, 2016, 01:41:57 pm »
This isnt a "built motor" this is still an oem motor with oem parts unless i missed something... i wouldnt go stage 2 until the warranty is done. You have been lucky so far with the warranty work.

Offline toytech

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #14 on: July 24, 2016, 12:49:51 pm »
Are they rebuilding the engine? Warranty can be very sticky on what you get to replace , i would find out what they are actually replacing . Sometimes warranty wont cover short block work if its just a head problem and i would want to make sure they are checking the pistons after driving around with a misfire for so long.

Offline funk32

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Re: 15 STI Idle & stall Issue / Cylinder 1 misfire
« Reply #15 on: July 24, 2016, 01:51:44 pm »
^^^ had a buddy in NB that had the same thing then they started it up with the same issue, had to take it apart again and found a piston with cracked ring lands.