So we found a vehicle, a sedan. No parts whatsoever.
I collected all the parts necessary.

By adding the first wheel, the vehicle started to slide down a slope but ended up in town. Adding a second tire got it sliding again. Adding the third tire, spark plug and battery worked as well. I could get into the vehicle, start it, but was unable to drive because of the missing fourth wheel.

After finally adding the fourth wheel I was UNABLE to get into the car again (also the passenger seat was not to be found and the spark plug couldn't be removed as well) but I could see the inventory. After logging in and out, same issue. I shot one of the tires because I thought it got stuck or something but no luck.

So:

• Before vehicle was complete, able to get in and start the engine.
• Now the vehicle is complete we are:

1.Unable to get into vehicle (after logging as well)
2.Unable to detach battery and spark plug.
3.Able to get into the inventory.

Update:

After attaching a headlight I was able to get in the vehicle again and remove the spark plug.