If you let your automobile insurance lapse, and the insurance company notifies PennDOT, then you could have the registration to your vehicle suspended. This happens as soon as PennDOT knows that your insurance lapsed, and it means you can no longer drive that vehicle in the state of Pennsylvania.
This suspended registration usually lasts 3 months, and that time will start once your surrender your pa license plate to PennDOT. As soon as they recieve the tag from your vehicle the 3 months begins and your car has to sit. You may continue to drive any other vehicles you wish, but the vehicle with suspended registration can not be driven by anyone.
You may choose to sell your vehicle prior to the registration suspension being completed, and you may sell the vehicle and the new owner can register the vehicle with valid insurance. Once the cehcile is no longer in your name the registration suspension is no longer a worry for you. You can purchase a new vehicle and with proper insurance and registration, you may continue to driver in Pennsylvania.
If you are stopped driving a vehicle with a suspended registration you can face suspension time being assessed to your PA drivers license. This suspension time will be 3 months and could go higher if other tickets are written (like no insurance 1786f). To complete a check of your drivers license, you can check for tips online for what to do if you believe your PA drivers license is suspended.
As a Pennsylvania driver you are responsible to maintain financial responsibility coverage on any vehicles you own and wish to drive in Pennsylvania. Failure to maintain the minimum of financial responsibility can result in registration suspension and enhanced penalties against your PA drivers license.