When my object tilts back the foreword movement lifts it off of the ground. how do i keep it grounded

If my vehicle hits a speedbump I can keep flying and hovering it around.

any thoughts?

Add gravity.
Something like this is solved here

Hmm…I think I have it figured out in my head, I just need to test it out. So, right now whenever the player goes off of a ramp at an angle, so he is tilted on his z axis, you can turn to look up and still move up. It is as if you are riding on an invisible wall and the forward movement of the character is overriding the gravity.

What needs to happen, is if the player is not grounded, the forward movement is null.

Unless I am just missing something simple and obvious

Thoughts?