No, because you are affecting the car's value by selling its parts. The car is collateral to the loan, so if you don't make the payments, the lender has the right to repossess and resell it to recoup their money. If they are unable to recover at least the outstanding balance of the loan through resale, you will be on the hook for the difference. This is called a "deficiency balance".
Simply having possession of something isn't adequate basis to decide you can do whatever you want with it. You have physical possession, but the lender is the first lien holder on the title until the loan is satisfied.