Hold on, i’ll upload a gif of what I think your weld script is doing and edit this post.
This is what happens when a script creates a weld with the old Roblox welding system for part0 and part1:
As seen the parts tend to go to the same position as the part0 unless the script edits the C0 joint CFrame which it might fail when spawning the car into the game as some parts of the game hasn’t finish loading in yet.
Might be better to use a weld script like in moon Animator which does it automatically for a model.