Misfire when Cold

[Fingaluna]

Hi Folks,

My X1 is misfiring.
Cylinder 1, 2, and random.
No misfires on 3, 4 that I can tell.
She runs like crap when cold.
Sometimes goes into limp mode, which clears after a restart.
When warmed up nicely, she runs fine (but codes do not go away, not that they would).
I have purchased the correct Delphi Coils and NGK plugs, same as OEM.
I have not yet installed the coils/plugs.

Do folks have suggestions on what else to check that will affect just 2 cylinders.
Will a bad MAF affect just 2 cylinders?
Head gasket maybe?
TPS?
Throttle body?
Already changed the ECU as there was a fault.

Just bought this car (120,000km on it) so I don't know the history. And no, it had no code when I bought it...

2012 X1 xDrive28i

Thanks!

[bosstones]

I don't know the quirks for your engine as I have a N55 but I don't think it would hurt to change out the plugs and coils, especially since you already have the parts. You could play swaptronics to see if moving just coils change which cylinders misfire and further dig down if you have the time and wanted to save money or just go for the gusto and replace everything.

If it were me, I'd just replace all the plugs regardless. It's an opportunity to get a health indicator of the vehicle and it won't hurt having new plugs. Worst case, you're out some time and the cost of the plugs.

Injectors are a potential cause that comes to mind as well.

I just recently did some maintenance, including new plugs and coils. I went from no misfire to single cylinder misfire. Turns out one of the new plugs was the cause. In the process, I learned that coils for a S54 will work on a N55 and seal REALLY well. <facepalm>

[Gamb1t]

I wonder if your cat clogging up. How is the car when you accelerate up to higher rpm? Does it feel strong?

Well changing plugs and coils are good practices at 100k km. At least you eliminate these sources.

[Fingaluna]

Thanks All,
I decided to bite the bullet and do the timing chain and oil pump chain as well as the plugs and coils.
$3,000CAD for the job, so not cheap, but she'll last me a good long time now.

[Fingaluna]

I will check the cat as well, thank you.

[Fingaluna]

Turns out it was the injectors.

[Fingaluna]

Hi All,
Hoping for some further help on this... Please!

I have treated the gas with Injector cleaner for 5 tanks. 91 / 94 Octane gas.
Cylinder #1 no longer misfires.
Cylinder #2 still misfires, but ONLY cylinder #2, and ONLY when cold.

So, I go the injector replaced today. Actually, I did 1 & 2 as I had bought two injectors. Yes, the injector programming was done.

At this point, I have done the following:
New ECU
New Coils (all 4)
New Plugs (all 4)
New Injectors (Cyl #1 & #2)
Timing Chain
Oil Pump Chain
Fixed some sh!tty wiring on the ignition wires
Inspected for Carbon build-up - Mechanic reports it looks pretty clean.

I have not checked the CAT. She runs really well at highway speed. Great acceleration.
I have not changed O2 sensors (not sure it would be this on just one cylinder)
I have not done a smoke-test (being done this week).
I have not checked Turbo pressure. I can hear a tiny whine from the turbo when I hit it, but it's really faint.
I have not done a compression test.
I have not changed the MAF sensor.
I have not checked the valves. Not sure if that can be done easily...?

She runs so nicely when warmed-up, but I keep getting codes... And occasionally Limp mode. And then the damn front windows won't work until I clear the codes, and do the anti-trap reset thing. Very strange to me that limp mode stops the windows working, but I have learned that it's to "reduce power use" or something. I likely have a bad window regulator as well, but I am going to fix that damn misfire before I fix anything else!

Anyone have any guidance for me here? Is there anything else I am missing?

Thanks All!