Read about Faraday Cages. Many things that lots of folks think won’t work (cars, gas pumps) are actually not as vulnerable as one might think. A car is basically a big Faraday Cage, so is a gas pump, encased in metal.
Also, in my research on this, I was surprised to find that EMP attacks are more localized than I was originally led to believe.
I did a bit of research on this, as I’m lately on a survivalist kick and I’m trying to prepare for any eventuality I can think of.
Not effective at the right frequencies to offer meaningful protection. There have been demonstrations of vehicles disabled by local EMP.