[Bob Mc]

A powerful enough EMP will "zot" semiconductor devices. In essence your car's computer is "fried". No it won't reset.

Old car's with mechanical ignition systems will be unaffected. The radio would be shot, unless it is really old and has tube type radio.

[Ghost of Philip Marlowe]

Are you sure the old cars would still run? What about the coil and generator?

[_Jim]

Old car's with mechanical ignition systems will be unaffected.

So will the new ones ... EMP is overrated, unless you want fear and panic ...