Hello i have a big problem, my car is invisible for others when im playing online, when im driving around the track, other people when spectate me see just a empty pitstop, I've formatted my PC, tried on other pc, tried to create another lfs account, nothing helped ....

holy shit man!!!!! you saved my day!!!! thank you !!!! BLESS !!!!!!!!

I get this everyday I play. When another session starts or a track changes I have to change packets sometimes when i just drive with few people their car dissapers. What is causing this and why, is it possible to fix in future?

yep, now i have to press ctrl + t any time i connect to the server

Basically when using UDP you just recive the car updates(with data ofcourse) while using TCP you send request for car updates (correct me if wrong).
As in Tomislav's problem maybe others just have bad internet, give me more details

both UDP and TCP just receive packets from server, but UDP packets are by design allowed to be thrown away by network, or arrive in unpredictable order, so it's essentially one of the first things to drop by network things when overloaded. TCP by design is "guaranteed" to be delivered and the client must confirm by acknowledgement back to the server each of them, which makes the protocol lot slower and more verbose than UDP.

Seems to me like your ISP or some ISP between you and LFS decided the UDP packets from LFS are not important, or maybe even suspicious, and they drop it purposely.