2011 SHO non pp. Just under 150k miles. LME tuned with SP-534 plugs ~.030" No oil catch can, never looked at oil separator. No low oil message and about 2k miles before due oil change. Don't believe to be fuel related even though my wife drove it the night before and fueled it up. I did the math, and she 100% put 93 in it. I was really hoping that was all it was.
Driving in to work on highway showed no signs of issues. I passed a few people per normal and hit 80-90 with good power. The last 3-4 miles is in town with stop lights. I first noticed a blinking check engine light and saw a P0305 (cylinder 5 misfire) and an O2 sensor code (not sure which one, but probably a byproduct of the misfire anyway) I cleared them and continued driving. Then at a stoplight I saw a bit more than normal smoking out the exhaust, white best I could tell. I noticed a little vibration and then CE light started flashing again. P0305, P0306, & P0300 (random or mult cylinders I believe) Vibration got worse, felt down on power even though I was babying it at this point and still smoking.
I got it to a shop that is walking distance to work. Admittedly, I only let them do tires and oil typically. I noticed some lingering smoke out the tail pipes after it was shut down. I let them know about the plugs assuming they would check them or at least 5 and 6. For some reason they took that information and decided to gap them to .040" even though they were all around .030" They then charged me 1.6 hours which amounted to $144 for re-gapping my plugs to the wrong gap which I specifically told them not to do! I will deal with that, but I believe all plugs were decent. I repeatedly told them to check coils and saw no mention of that in the report. When talking to them, I mentioned that I had a bit of a concern for the turbo seals especially the front since it was 5 and 6 that misfired. This was more just that panicking out loud thinking you do when worrying about your repair bill. I now think he took that and ran with it because he didn't want to deal with it. Thinking about it now, the turbos dump into one intake and feed all six out of one intake so I don't think that logic was sound. So $224 and a job they won't do with a diagnosis I question is where I am now. They got a quick pay day and punted it seems. I know I can do all six plugs in about a half hour.
I plan on taking it to the dealership, but was curious what a failed turbo experience is like. Is the exhaust smoking a "smoking gun" for the seals, or does a simple bad coil causing misfires smoke as well? Will there be any external oil leakage I could see simply with the hood open? Anything else to consider?