Hello everybody, there are some achievements that won’t unlock, the achievements app says: “DONE! Unlocking…” the achievements are: “A Quarter Mile at a Time”, “Just don’t scratch it”, “Fully Charged” and “Drift to Win”.
there is also another achievement that won’t unlock, and it doesn’t even say “DONE! Unlocking…” (I did it 4 times!) the achievement is “Too Soon Junior”
HELP! 
It sounds like you may be experiencing an Xbox Live and/or Forza server connection error which is preventing the achievements from unlocking completely. What happens when you attempt a complete console power cycle? This is, for all intents and purposes, the first step in troubleshooting and often resolves issues.
I forgot that exists! I’ll try that and reply here if it does not work, thanks!
YEAH! it worked, thanks a lot dude!!!