The vehicles will stay once you drive them. You must put all the parts in and start the vehicle to save the parts and vehicle. If you put some parts in and then go to get other parts in a different area, your vehicle (and the parts inside) might despawn. Once you have all the parts and you start it, the vehicle will stay forever (unless someone steals it).
If you pull a vehicle up to an electric meter, outside of a structure you can use it like you would use a generator.
true , alright ill be more mindful in the future.., when do you think the full game will drop ? enjoying it but I do see a lot missing so not rushing or anything in terms of that, pls be as patience as needed,but wondering what u guys would be doing in pvp terms.. when game drops fully gas stations will always be owned by players