The automatic stay would prohibit repossession of the vehicle. You would have to pay the current monthly installment of principal, interest, and insurance due on the car as they become due, in addition to the monthly payments under the plan in order to keep the car. You choose a percentage or amount to repay to the unsecured creditors through the Chapter 13 plan. This percentage or amount of unsecured debt repaid through a Chapter 13 plan is usually equal to whatever equity you have in your assets minus your exemptions. What you have to pay your unsecured creditors through the plan depends the amount of equity left in your assets after deducting the liens and your exemptions.
Unsecured debts are money obligations for which the creditors hold no lien.
For example, most credit card bills, doctor bills, hospital bills, deficiencies and many loans. It must be feasible. You do not have to continue to pay your unsecured creditors, because they will be paid through the plan. You have to continue to pay your current mortgage and car payments, while at the same time paying the installment payment required by the plan. This sounds very complicated.