DISCLAIMER!!
I’m not confident enough to say this is definitely going to help everyone, or that it will actually helpwith these problems at all, it’s too early to tell right now.
However, after 11 days of misery trying to play online i’ve now managed to remain connected to not one but two different lobbies today for well over 10 consecutive races. This is the first time i’ve managed to do this despite hours of trying since the november update and i believe it all comes down to two simple things, hence i thougnt i’d share early on in case it helps others a d maybe even T10.
PROBLEM #1 - being disconnected seconds after the race begins or sometimes during the loading screen.
There seems to be a strong correlation between selecting a car or loading a tune then having this occur on the very next race. If you’re like me you might have several tunes for one car and depending on the track you will load up the suitable tune once you see what track it is. This entails a mad rush during those precious 45 seconds you have of not only selecting the right car but then loading the right tune - here’s the kicker, since the update if you haven’t got past the “please wait saving” prompt BEFORE the 15 second countdown has begun it’s almost certain you will get disconnected. Given the saving portion of this process takes around 15 seconds it doesnt leave you with a whole lot of time and why i think it’s happening to so many people (but then others it rarely seems to)
WORKAROUND #1 - avoid the “please wait saving” prompt by any means necessary
For myself, instead of having one car and loading different tunes, i’ve flipped this around and have started having numerous same cars each with a different tune pre-loaded then i just select the right car before the race. Sometimes hard to know which is which if the stats are the same but if this proves to work i’ll prolly choose different paint colors to get around this.
By doing this it still allows me to have the right tune for the track but will entirely avoid the “please wait saving” prompt. Avoid that and you will avoid the disconnections (well maybe not entirely i just got one for inactivity whilst typing this but the generic “you have been disconnected” errors should decrease significantly as they have for me)
The downside is that you need to buy multiple copies of a car you already have, so this might be a problem for some people who haven’t yet got much credit banked and the expensive cars.
Isnt it great you can now purchase tokens and not use credits for this cough If you do fall into this category i don’t advise giving T10 your money to avoid a problem they have failed to identify and fix for 11 days, send them an email or something and maybe they might be kind and give you some tokens or credits, i think its the least they could do to be honest.
Worst case, choose the best car you have without the need to load a tune so you simply avoid the “please wait saving” prompt and you should hopefully see a reduction in the disconnects.
PROBLEM #2 - unable to find a game session / match / lobby type errors
Once you’ve hit problem #1 something behind the scenes is stuffing up and you’ll then basically get these errors almost consistently no matter how many times you retry or how long you wait OR you get thrown into a lobby with 1 or 2 people. I’m not entirely sure why this is happening other than the disconnect issue is triggering something to happen behind the scenes which then causes the matchmaking to put you over to the side with other hopeless people suffering the same drama. Maybe it makes the xbox run like crap and you latency goes up or maybe its magical unicorns. I’m yet to work out the most effective way around this one but so far it seems there is only one thing which helps but not as much as problem/workaround #1
WORKAROUND #2 - reset your xbox
Has to be a proper reset not just the standby off/on. Choosing the reset option in the left twist menu thing is fine it seems, you don’t need to yank the power cable or hold the button on the front of the box for 15 seconds, but if you want to be thorough do either of those options as its guarenteed to be a proper reset then. Basically make sure when it powers back on you are staring at the green loading screen for a while which is equivilent to the “starting windows…” one for PC’s. Microsoft seem to want to avoid the long ago stigma of the having to reboot windows every few hours from memory leaks by calling this “clearing your cache” for the xbox but it’s awfully close to the same thing, the marketing people must have worked hard on that one 
Fingers crossed the problems actually get resolved by T10 sometime soon if i’ve merely had two really lucky runs today and the above doesn’t help at all. It would be nice if T10 would even just acknowledge the increase of people having issues, but since that seems to be a no-no for them heres hoping i’m onto something and this works for others…