Jerry Emanualson is an electronics engineer who has been thinking about the EMP problem for more than 3 decades. This is an excerpt from his book Getting Prepared for an Electromagnetic Pulse Attack or Severe Solar Storm. I feel it is correct but you need to do you're own research and make your decisions accordingly.
One thing that you'll discover in that Critical National Infrastructures Report is that automobiles and trucks seem to be more resilient against EMP attacks that what is portrayed in most fiction. Although many vehicles would be rendered inoperative, and it will be a regular "demolition derby" on streets and highways, many (but not all) vehicles that are not running at the time of an EMP will be likely to run after they are started (although there is a very high probability that your car will experience electronic damage outside of the electronic ignition system, and your car may have to be started in an unconventional way. It is also possible that you may have to momentarily disconnect the battery so that electronic modules can recover from an EMP-caused latch-up condition, a situation that, in automobiles, is unique to EMP.) It may be necessary to have a maintenance manual for your car so that you, or someone you know, can figure out how to bypass the damaged modules in your car.
Vehicles, especially gasoline vehicles, have to have a robust amount of electromagnetic shielding around the entire electronic ignition system. Otherwise, the ignition noise from all the automobiles would render radio and television sets unusable (especially car radios). Today's automobiles have published standards for electromagnetic shielding, but there is not much consistency in shielding requirements.