Standard assets car going through the floor

I currently have an issue where i have put the car controller into my game, and fixes the issues with the scripts for it. Yesterday it was working absolutely perfectly, yet today it refuses to work, and the moment I press forwards or backwards it decides to clip through the terrain. I have had a similar issue before on the same computer except when I pressed play all of my rock assets decided it would be a great idea to ascend the heavens. Does anyone know how to stop my car from falling through the floor?

Hi @Prancing_deer ,
Please make sure that the car has collider and also the floor has collider and make sure that either one has a rigidbody so that collision works… but much better if rigidbody component is attached to the car