Hard to do given that most cars are pretty-good Faraday cages.
You might be able to get some temporary interference with engine management, doorlocks, sunroofs etc but I seriously doubt you'd do any damage - or have any real effect.
Cars tend to be tested against things like radar pulses, for obvious reasons, and only freaky-weird stuff like Fylingdales causes problems these days
Having said that, one of my colleagues had a Fiat Uno in the late 80s - one of the early really common cars to have sophisticated engine management. That refused point blank to do anything at all on a BBC World Service site - we had to push it 100 m down the drive. But then, the one we had often did that anyway
Carbon/glass fibre panelled vehicles might well be more susceptible. But i reckon something like a Taser, that injects pulsed current direct into the structure, could be far more effective at disabling a vehicle.