You are only eligible to discharge debt made before bankruptcy. Once your case is filed, you are legally obligated to pay any debts you make after the filing date.
Hope this perspective helps!
I understand that you mean you filed for a Chapter 7 Bankruptcy and then went out and purchased a car while your Chapter 7 was still pending. If that is the case, then no, you can not add the car to your bankruptcy, since you did not owe that debt on the date of filing.
If, on the contrary, you bought the car just BEFORE you filed the bankruptcy, then you have no choice. You must amend your petition to show both the asset, on Schedule B, and the debt on Schedule D. And you should do so quickly, before the Court has a chance to catch you with your pants down. It would be a big deal (think possible felony) to fail to list a car and car loan on a Chapter 7 Bankruptcy. Listing all of your debts and all of your assets is NOT optional. Good luck.
The important date to consider is when your bankruptcy case was filed. If you purchased the vehicle after the case filing date you cannot include it in the chapter 7 case. Now, if the car was purchased before your case was filed you still may be able to include it so long as you did not sign a reaffirmation agreement. Likely, you are on your own for this debt if the vehicle was purchased after your case was filed. It would be best to consult with your bankruptcy attorney and explain all the facts of the situation.