Owen is right-- When a radio-man , had a guy come
into the shop, complaining about his truck
stalling when he transmitted. (freq around 160
MHz) Ran his truck, (idle), keyed rig, NO
Problem! Said to take it for test run- in low
gear, (abt. 2000-2500 rpm), and keyed the
transmitter, the rig STALLED! Wasn't a problem
when I installed radio- turned out they had
modified the truck to an Electronic Ignition!
This around 25 years ago. Tried various cures
but, they went back to the original "Points &
coil" system and worked fine! (this before these
were common on vehicles). Translation: YES, can
effect a vehicle, but times have changed: might
not be so supsceptable now a days (more problems
with the built in computer that they seem to
like to hide-- drill a hole in these- turn a car
into a thrashing machine! ). But BOTH can cause
problems. btw the power level for the problem was
a 50 Watt radio. and the SECOND problem (think
they more standardized now), could be placed
as the manufacturers stated, (ANYWHERE in the
vehicle) ! Now days must be within 3 foot of the
OBD2 Plug (used for smogging)! At least in the
U.S. As info, Jim NN7K

Owen Duffy wrote:
That design
problem was probably fixed rather quickly.

Back in the '70s I was working on a project that saw me reading papers on
the effects of EMR on various things. Amongst the papers was one dealing
with the susceptibility of the electronic anti-skid technology introduced
on heavy transport vehicles to meet (then) newer more stingent braking
distances. The braking systems were susceptible to ingress of RF,
resulting in wheel lockups. You can imagine the results of a 22 wheeler
at highway speed when a chook alongside comes up with "Breaker, Breaker,
any taker?" and locks up most of the wheels on the transport. I read
other papers on rear wheel lockups in a certain brand of passenger
vehicle due to RF induced downshift of the (electronically controlled)
automatic transmission at highway speeds.

The EMC issue seems better understood by vehicle manufacturers today,
though you still hear of RF triggered airbag deployments from time to
time.