Actually, there is only one crank sensor, and it's a "7x" signal. From our repair info, which gets their info straight from the manufacturer, without reformatting it, here's what they say about the cam sensor: Basically, without the cam sensor, misfire detection may not be able to determine which cylinder is misfiring, and it won't know which injector to fire out of each cylinder pair (1-4, and 2-3) so it will fire each for that cyl pair at the same time, which COULD decrease fuel mileage, and increase emissions, but most likely not enough that you'd notice much other than the light being on.