It wasn't aim at you but @Chevycopper that was pushing disinformation or just showing his lack of knowledge about these.
But normally when one of these fail you will not even be able to start the engine. Now loose terminals on the wiring harness can cause intermittent problems with them. I have the best mechanics get sideline by loose connections. The ones that work until hit a bump especially. Even a nearly clogged fuel filter or faulty spark plug can minick the problem you are having. It takes pateince and experience to troubleshoot these kinds of problems.