The following few paragraphs are going to be a quick history of what I've been dealing with. If you want to skip this part then I will have a marker for what I am currently dealing with and below that will be a quick summary of everything that won't be as long winded.
-History-
My 2016 2ss for the last 8 or 9 months now has been idling rough on cold starts especially in the mornings. It feels and sounds like it has a big cam in it for about 10-15 seconds then it calms back down and runs smooth as always.
Every since I first experienced it I have been trying to get to the bottom of the issue. It seemed to get worse when the temps here in Illinois were in the -20 area. (If there is snow or chance of snow I drive my jeep, just so a select few guys don't yell at me for driving my car in the winter).
So occasionally I will get a flashing check engine light for about 20-30 seconds after start up after it idles (more like chops/misfires) but every time I took it in to my dealership they have told me there isn't a light that comes on and seems to be a normal cold start.
Especially in the winter I would occasionally get a solid check engine light and the guys are Oriely's read it for me. It read "P050D - Rough Idle on Cold Start". Below that it has a not that says "No action needed".
So I took it back in to my dealership with the print outs from Oriely's and got the same sort of deal. "Well there is no code on here and we can't really do much if there is no code on while it's with us."
Starting to get upset at this point I picked up the car and brought it home. I have been driving the car as normal for the last couple months now and it seems as it's getting warmer the code doesn't come on anymore other than the random flashing check engine then that goes away. The car runs like a top as soon as it starts warming up as it should.
-Current Situation-
I took my car into a new Chevy dealership for it's service yesterday morning. I have been starting to get frustrated with the original dealership I bought the car from.
I told them its just in for a oil change, multi-point inspection, and it has an appointment with the detail bay to get its spring cleaning done. I also told them about the rough idle first thing every morning when you start the car. They said they will check it out and see what's going on.
Last night I received a call from the service manager. He said "So we felt the rough idle cold start like you mentioned and something defiantly isn't right". "We are going to leave it here again over night check it out again in the morning to see if we can identify the root of the problem".
At this point I am thrilled someone it taking it seriously. I wan't ready for how serious this issue could be though. "I have only seen one other case of this in the last couple years and it was with another 2016 camaro ss". He then followed with "This is worst case scenario but I want to check and make sure that you aren't getting antifreeze in your cylinder over night". He said that "What could be happening is that over night some antifreeze is leaking into the cylinder then in the morning when you start the car it misses in that cylinder because it has antifreeze in it and takes 20 seconds or so to get it out and then the idle returns back to normal".
My heart sank and I realize this could be a much bigger issue than what I previously thought. This morning they are going to put a oscilloscope down the spark plug hole of that cylinder and see if that is indeed the issue. He said it could also be a bad injector or even something wrong with the ECU.
-Summary-
I have been dealing with a rough cold start idle since the fall and It seems to have gotten worse over winter in the freezing temperatures. After about 20 seconds it goes back to a normal smooth idle and runs like a top especially once it starts to warm up. I took it to my dealership and they told me that it seems like nothing is wrong. I took it to Oriely's to have the check engine light that comes on occasionally and they said it is "P050D - Rough idle on cold start" with a list of issues and fixes to correct it. My dealer again told me that if there is no Check Engine Light on when they have it they can't do much.
I took it to a new dealership yesterday Tuesday night for a service, spring inspection, and detail appointment. I told them to check out why it idles so rough in the morning. They called me back yesterday and said there is defiantly something wrong. They think it could be as serious as leaking antifreeze into the cylinder over night which is causing the missing every morning. They will be putting and oscilloscope down the spark plug hole this morning to see if our worst fears are real or not.
-Conclusion-
I am now anxiously waiting my call from the service manager to give me the verdict and what they are going to do to fix it. I will update this thread as soon as I have any news from the dealership. Please feel free to share you opinions and past experiences if any of you have had this same issue.
Thanks all, happy Thursday!
