I have had the following two things cause vehicles to spin like that:
If the mass of the vehicle is too low, the weight of the character can cause excessive vehicle response. I couldn’t see the assembly mass in your vehicle. I suggest trying to increase mass/density on a part as a test.
If the vehicle is positioned low the springs may be compressed and cause the car to jump up and over respond on start. Try placing the vehicle up just a little and see if that help.
There are many possible reasons here, though the following are the most likely causes.
The 1st : Weight Balancing, the vehicle may be glitching out due to weight from different pieces of the vehicle, that the springs are unable to handle the weight.
The solution here would be to set Custom Properties / Massless.
The 2nd : Weld / Collision, the vehicle may be glitching out due to false welds / collisions, closely related to the wheels, affecting the springs in the process.
The solution here is to locate the colliding pieces and set CanCollide.
The 3rd : Excessive Force, the vehicle constraints may be under too much force from single / multiple sources of force being applied to the vehicle, this can also relate to negative values.
The solution here is to adjust the values of each constraint respectively.
The 4th : Code Conflict, this may be related to how your vehicle is coded and generally how it works, the handling of the vehicle, this may be a factor on how the vehicle is glitching out.
The solution here is to modify the drive scripts.
All of the above is under the assumption that the vehicle functions as expected without springs and there is no other influences from workspace.
I would recommend testing and trying each solution until there is a change and continue working from there.