White exhaust, CEL flash and exhaust pipes shaking

[Sgtmeatsauce1]

Dirty injector .......

 

[6500rpm]

Check for coolant loss. The two code tell you what cylinder (2) and that it happened at start up. Flashing check engine light was due to a heavy misfire (catalyst damaging misfire). Usually white smoke is coolant related, but I could see that enough fuel in the cylinder could foul the plug-either could happen as the car sat. Things like bad fuel typically effect all cylinders, not just the one and you throw lean/rich codes to go with the misfire dtc's. Best case would be that an injector held open and some how cleared itself. I'd let it sit overnight and pull #2 plug and check the condition and take a peek down the cylinder with a bore scope if you have access. After seeing the coking issues on the DI engines at work it's made me a true believer in good gas and good oil. I had a 2017 Tahoe in last week that GM is having cold start up misfire issues with that have a TSB to check for mismatched injectors bank 1 to bank 2, or case 2 is coolant leaks in the runner. On this particular vehicle it had one valve that was visibly cleaner than the others and I was leaning toward pulling the head and was told by Tech Assist to go with new injectors on that bank and come back to the head if the problem comes back. I had it set in my head that DI engines didn't hit the intake valves but by his response, on at least some designs they do. Unfortunately the valve stems still coke up a lot more than I'm happy about. Probably a bit more information than you needed and a bit off topic but it was kind of an interesting observation.

 

[SHOdded]

On a recent visit to the mechanic's just this past week, I was advised that GM had dropped the OCI intervals from 7500 to 5000 due to issues with the VVT systems. IDK if this is across the board, but ... yeah.