Started the Burb yesterday morning and the cabin wreaked like gas the whole way in to town (5mi). Drove in to the dealership and parked outside. Left the Burb there after talking to the service rep. Got a call at 5:00p that they didn’t find anything. Said they had it up on a hoist and couldn’t find any problems and no TSBs (?). Personally I think the issue is up by the engine, under all those plastic covers. The only thing I can think of is heat kind of “seals” or masks the issue because it’s not as noticeable after driving it a while. I’m assuming it’s leaking where the heat is evaporating it. So now I have to try and drop it off when the issue arises which seems like it’s every cold start. Maybe I should have left it there to have them start it in the morning. Nonetheless I’ll keep trying to hunt this down.

It went back in on Wednesday. Luckily they could smell the gas in the cabin and under the hood when I got there. Got a call yesterday that they found an open bulletin on a similar issue. Something to do with o-rings on the injection pump and injectors. Hopefully I’ll get few more details. Likely won’t see it till next week so will have a loaner till then. Will report back with more info next week.
It’s hard to be frustrated when it’s common sense that these things can happen, even if they are new. It’s under warranty and they put you in a 2018 Silverado. I guess if I was paying for the parts and labor it would obviously be a different feeling. First time I’ve ever had a vehicle in for warranty work so new to this.

Got the Suburban back yesterday. Talked to the service gal and they found a defective o-ring on injector #2. They replaced all o-rings for preventive maintenance. With 1740 miles on now, hopefully I’m not back in at this interval..
Will see how it goes this next week and see if it’s resolved. Just thought I’d post back and let you know what they found.