Gearhead Garage: The Virtual Mechanic [cheats]
To fix any and all repairable parts while they are still on the car without having to take them off, press [Delete] + [End] + [Page Down].
When you are in job mode, press [Insert] + [Home] + [Page Up]. The job will automatically finish, you get to keep your money, will get paid.
Take parts off people's cars then enable the "Free job" code. You will still have the parts under that car name and still get paid the full amount.
When doing jobsstrip the car of all its parts and then go to the action and buy the car you just got all the parts for and scrap all the parts you got with the car when you bought it and use the parts and you will be + money when you are all done after striping the car use the free job cheat.