I like that, minus the environmental impact of the gasoline spilling everywhere. Why not also have the car's doors and windows lock so that the thieves are trapped within? :)

Well, the gasoline spill was only an example. I am not a mechanical engineer, nor have experience with cars, but I'm sure any of you would think a safer, quicker way (brakes? engine?).

Locking car doors and windows might not be practical as these people are very well armed... besides that, frequently they work in team, with fellow robbers who follow them in another car.

Refine the idea. Give the thieves five or ten minutes of usable time so they don't hurt you for disabling the car.

Wipe the ROM on any new car's computerized engine.

Good idea - how about a foot switch above the accelerator so they don't see any movement ? Link the switch to the ignition or to cut the accelerator cable if you do'nt want the engine to stop running.

If you are stopped by thieves and forced out of your car, would it be a good idea to frustrate them with an obvious mechanical method? It might be very likely that they would take their anger out on you and injure you seriously and perhaps kill you. Something more subtle like a global locater might be able to trace your car after they leave you behind, and perhaps save your life.

it seems to me that if you wired the output on the alternater to a switch(out of site), the car would run until the battery died, which usually doesnt take very long. the car would would remain dead until the battery was charged and the switch thrown back to open.

I read somewhere that some cars have timers that allow the car to drive a little ways, but then have the engine quit. It seems that cars that won't go when the armed thieves say it should become a safety liability for the original driver.

In other words, what was a carjacking turns into murder when the PO'd carjackers can't get their prize to go anywhere.