Hey DannyG - welcome to the group. Sorry to hear about the shuddering problem, but yes it looks like you've at least come to a place where we can put our heads together on this.
First I just threw up a bunch of links
here that may be of interest for you guys with this problem.
Second, I think that maybe making an open Google Docs spreadsheet recording your handle on here, vehicle year, trim level, engine, drive wheels, VIN #, and mileage you first started noticing this would be very helpful, if someone wanted to do that. . .
Who knows, there might be a very clear pattern in VINs or mileage or something that we're not picking up from these sporadic reports but that would be very obvious if they were listed out, even just a handful of them.
In the mean time, I still think doing a ride with a mechanic in your vehicle, showing the problem is real, then riding in a brand new car on the lot and showing it's absent there should be reason enough for them to take your car until they can find out what's going wrong. It's an agressive technique
, but I'm somewhat concerned at the #s of reports now. I also wouldn't wait until your 2nd oil change unless it happens to be this week or something.
Super critical for anyone experiencing this (or any sort of chronic plague of a problem under warranty): document your actions very well, if you bring it into the dealer save the invoice and then make a dated note any time it acts up again and immediately make another appointment to bring it into the dealer. God forbid it's a serious problem, you'll only get help if you can show how they were unable to fix it over x # of visits, etc., etc. This is how I got Honda do "goodwill" me an entire $3k air conditioning replacement when I was 5k miles out of warranty, it's because I had a stack of well organized notes and invoices for the 20k miles leading up to it. BMW paid $3500 for a new transmission for me last year for a car that was like 6 years out of warranty. . .If you end up getting something fixed or replaced at an independent shop, save those too - Audi paid me back for catalytic converters I replaced one time, that was like $2k. Good records are a life saver.
Personally I scan everything auto related (invoices, receipts, etc.) to have "hard copies" and I also maintain a Google Doc spreadsheet where I have space to write in more notes or things that might not have an invoice.
Open to ideas on how we can attack this thing!