As I understand the nature of a nuclear EMP, most of the energy is below 100 MHz. Many automobile electrical systems will survive due to the steel Faraday cage-like structure in which they're enclosed-- maybe -- the car still needs gas. Then again, that FM radio thingy in most cars is right at +/-100MHz with an antenna that takes what's outside and brings it inside, hmmm. I wonder how much a spare computer and other components would cost; cheap insurance? or is my tinfoil hat showing

Fortunately, with a car the EM pulse only has 2'-3' of radio antenna to couple into the car's system, which may limit the damage. Most of the serious infrastructure damage is caused by the miles and miles of wire the EM pulse can use to couple to our electric grid. That's where the huge spikes come from.