[Jay.]

Here is something that might help you. I had this problem before too , but this fixed it.
It's a function related to the streamer you are using.

Little example of how to use it:

pawn Код:

if(GetPlayerState(playerid) == PLAYER_STATE_DRIVER)
              { Streamer_UpdateEx(playerid,3134.690,-1667.340,608.922);
                SetVehiclePos(GetPlayerVehicleID(playerid), 3134.690,-1667.340,608.922);
                SetVehicleZAngle(GetPlayerVehicleID(playerid), 0.0);
                LinkVehicleToInterior(GetPlayerVehicleID(playerid), 0); 
              }

//So first you use

Streamer_UpdateEx(playerid,x,y,z);// your coords

//then you use your 

SetPlayerPos(playerid,x,y,z); // same coords as the UpdateEx

It even works with SetVehiclePos.

Try it