Why has my Tween gone completely insane?

Oh. My. God. My Tween is extremely broken. So basically I'm making a thing where it has how many players are in a vehicle and how much time is left before they teleport somewhere, I'm trying to get the vehicle to Tween when the time reaches 0 or when the players are maxed out (right now I've made it 1 player for testing) and my tween is doing nothing I said, I put a Vector3 value as it's position, but when I get in it, its just bouncing around and not going anywhere, it flips upside down then starts leaning back and forth, if I wait for the time to finish, it goes to a completely different direction, starts doing the bouncing around, and then just glitches and flies across the map

To the admin that told me to explain it more: I don't really know what more I could explain, I said what I wanted to do- to teleport players when there's maximum capacity in the vehicle or when the time runs out-, I mentioned that it's a model and welded to a part, I included my code, and I tried to describe the problem, I really don't understand this strange event enough to explain more

ALSO NOTE THAT THE VEHICLE IS A MODEL AND THEREFORE HAS ALL IT'S PARTS WELDED TO ANOTHER PART FOR TWEENING

My code:

local Tween = game:GetService("TweenService")

local Tweening = TweenInfo.new(5,Enum.EasingStyle.Quart,Enum.EasingDirection.In,0,false)

local TweenGoal = Vector3.new(-138.714, 537.721, -137.387)

local Tweened = Tween:Create(LeftRoot,Tweening,{Position = TweenGoal})

Tweened:Play()

end)