I wonder how effective an EMP would be at "sterilising" a vehicle of such trackers. Especially if the vehicle in question has no electronics and uses a mechanically-injected diesel engine.
Certainly an interesting thought if you have a very old diesel. I would wonder if all the metal would hamper an EMP pulse that you could safely generate at home.
Diesel's going back 20+ years still have ECUs as well, not to mention the rest of the vehicle's electronics could be at risk. So it would have to be a properly old or unique vehicle.
It's an interesting idea. The "obvious" route would be to tear down the vehicle and remove all the ECUs you want to save, then administer the zap. But at that point you probably find the tracker hardware anyway, unless it's really buried in some upholstery or something.
I would also want to be able to check for trackers regularly, which excludes a full teardown. I would want to check these particular kinds of cars after every event they go to for example.
That said, whilst it is a known threat vector, I have no data on how often its actually exploited. It might be a lot of work for nothing.
The last car without electronics I drove was a Tavria made in Soviet Ukraine 35 years ago. Then dad installed an aftermarket ignition timing chip. You need to go really far back in time to find vehicles without chips.
