I have a R59 S 2014. These are some of the things that fixed my car buck up to run again.
first thing was that I had gap my spark plugs wrong because of what the package had it set on.
plugs was set at .o35 and did ok for a little bit.
long story making it right to the point.
Set the plugs at .028 and never worry about starting in cold weather again.
motor run so much better now.
at one point it had been taking up to 15 mins to get it started.
set the plugs at .028 and that fixed that problem after months trying everything to fix it. So hoping this will help others on this problem.

Then 2nd one is this one.
car would crank up and stop running after maybe a minute of running.
long store short here. It was just one bad coil that caused this problem.
work on this for over months. Wanted to just burn this car up because of this one thing. Changed just about every thing on this motor. Put in new timing chain, water pump, all the sensors that this motor has. Not fun at all.
the coils was not old at all. Had changed them with plugs with less then 5,000 miles on them.
after driving this car to the store and back, the car started missing and had to pull it my home. I had just changed the timing chain and sure enough I do not put in new cams bolt’s with it. Cost just $ 12.00 dollar for new ones. The kit sure needed to had them in the new kit, but it did not come with them. Never heard of this before with all the cars that I had work on before. So still leaning stuff the hard way.
so after doing all of these changes the motor still did the same thing. This was killing me trying to get this car running again. I am handicap and did was not easy for me at all. Never in my wildest dreams would I had thought that a coil could cause of of this. Now understand why a car garage will not work on these cars. Can not blame them at all and now understand why.
spending a lot of money learning all this, so I thought maybe just maybe others will check the plugs for gap and check coils For one going bad and cutting the engine off.
but I have learned a lot working and cussing this car now. LoL
just two things that worked before timing chain and just a little time after it was changed.
I think the problem was that I did not bleed the air out of the water before driving it to the store causing the coil to over heat and go bad.
still today can not understand why it does not have gauges for water/oil/volts.
so just because I did not bleed the water after changing timing chain cause a world of hurt.

 

First mod I did on my 2012 Coupe S was add oil pressure and water temp gauges. Those two gauges can save a lot of headaches if a problems arise, at least it let's you know where an idiot light is normally too far after the fact.

It has been a couple weeks since I changed my plugs, NGK iridium, I forget what the gap was preset to but all were the same. I have never had a cold start problem.

 

That is quite the story, thanks for sharing.
I have had issues myself but not to your extent.
For extra gauges I keep my scan gauge hooked up all the time.

 

I loved my Scangauge in my Chevy Duramax pickup! It cannot do oil pressure in my mini so I went traditional gauges mounted on either side of the tach. I also have Torque Pro on my radio that displays boost, ambient air temp and intake air temp, Air/Fuel Ratio and a couple other items.

 

Wanted to tell others about , if you can not open your trunk sometime. I found this out on as my wife was trying to open the trunk on out 2015 R59. I was setting in the car as she was coming back from the store and wanted me to unlock the trunk from inside the car.
we had tried three or four times, before I realized that I had the top open from the windshield side to help cool the car as I was waiting on her to come back.
the trunk will not operate unless the top is close or open all the way. Same thing for the top to operate . The trunk has to be close all the way to work the top.
hope this will help someone sometime.

 

You can add to the trunk not opening the fact that one can't open the trunk if a person is seating in the car with the key. The key Needs to be outside. Go figure!
I always get frustrated when I want to help my wife empty the trunk after the grocery store but need to have her hand me her bag or the key to open the trunk.

But hey, I forget quickly once I get to drive it