It's not a far-fetched idea. Two years ago police in Austin, Texas arrested Omar Ramos-Lopez for disabling the engines in 100 vehicles.
Farr says hackers could plug directly into your car's computer, or hypothetically access it wirelessly using the remote or Bluetooth. Researchers even loaded a bug into one car's computer using a music CD.
"When they put the CD into the player it allowed them to get to the braking system. I'm not sure they were able to do anything to the braking system, but they got there. That's the big deal here," said Farr.
That's the fear. That hackers could compromise your car, shut off the engine, or disable other safety features.
Experts say there is no epidemic of car hacking, but warn of an emerging threat as car owners rely more on computers and technology.
Before selling your car, Farr suggests drivers also wipe their car's computers clean. Delete contacts and GPS locations like your home. At least three major studies issued similar warnings recently, that hackers next targets might be on the road.