Good morning Sir, F150 2004, My truck runs good for about 15-20 miles. After that it seems as if the idle is not set right, aftherwards the vehicle turns of at every stop. But only after running the vehicle for a while. Autozone trouble shot it and told me the cam shaft sensor was bad. I guess my question is, if the sensors where bad, would it take a while for them to give me trouble? or might it be something else?