Hi and welcome to Just Answer!According to current tax law regarding collection procedure - the IRS MAY register a lien on your car and any property you own.They MAY take away your car as well. However unless that is a luxury vehicle and if that is your only car - it would be very unlikely that your car would be taken away to satisfy your tax debt.However - it is very likely that a lien will be registered and it will be reflected on your credit report.
The best way in such situation would be to negotiate a payment plan. If you would not be able to agree on payment terms - the IRS will start collection efforts
what about an uncollectable debt
The tax debt become uncollectable after the statute of limitation runs out.A general statute of limitation for federal income tax purposes is ten years after the tax liability is assessed.