Is there a low oil pressure sensor/switch that prevents the car from starting if the oil pressure is low? The reason I ask is because when I checked my oil yesterday, in the process of trying to figure out what may be wrong, oil wasn't even registering on the dipstick. I added a couple of quarts, tried starting it a few times and it didn't start. About an hour later I tried it again, it started. Shame on me for not paying closer attention to my oil. Could this be it or do you still think I have a failing CPS or ICM. I went home changed my oil and filter. I even bought a new CPS. Looked at where the CPS was located and figured I would try to wait for the weekend to mess with it. By the way, what size is that nut holding it on?