Also, once you hit the "E" key, the vehicle must go thru a "starting pause" before it will roll.
So if you hit the "E" key, then the "Q" key, and then push the stick "forward", the vehicle WILL NOT move forward and in most cases, it will move backwards ... like it's in neutral ... until it actually has finished the "starting pause".
The "starting pause" is actually the length of time given for the vehicle start engine wave to play. Once that is complete, the vehicle will move forward when the stick is pushed forward.