ABS as in the braking system? So rpm is rpm of the wheel?
yes
Do you have multiple sensors or multiple magnets activating a single sensor?
3x sensors with approxmatly 60 triggers per revolution
basically what im trying to do is for my arduino to look at 2 of the sensors and pick the fastest travelling one and compare it against the 3rd one if it is going slower than the 3rd sensor then to execute another piece of code