Hello, so whenever I join a multiplayer game, it disconnects me because I'm 'running to slow'. My specs bottleneck a bit, but not enough to impact my frames significantly. I have an AMD FX 6300 (6 cores @ 3.5 ghz) and a MSI GeForce GTX 970 4GB. I use a command line for 4GB of vram, but when i try to start my own lobbies, I freeze and go to the ocean looking over liberty city view, then crash, or It put me in my own lobby and does this. And when I try to join one, it will do infinite loading, starting a new game (and put me in my own lobby), or go past the lobby and crash because my computer is running to slow at the 4 fps loading to join the lobby. PLEASE HELP! I had this issue before. I use LCPDFR 1.1 and I have VSync off. 

could be your internet...

Remove your mods, and then see what happens. Be sure you're graphics are optimized. Also, be sure your screen resolution is high. Sometimes some car mods are high detail and they require a certain amount of available memory to function well. 

There is a fix listed on the DevBlog. I don't know how to access the multiplayer files though, if you can, that should fix it.