I assume the crank position sensor is what gives the tach it's signal right? I have some issues with my cars tachometer. Usually it would happen in the winter time when it was VERY cold out until the underhood area got some heat. I have determined it's not the needle dragging on my gauge faces. When spring/summer comes, the problem only happens on rainy days. Tonight, i washed under my hood real quick. I didn't really spray the motor down, just washed the front radiator area and inner fenders and gave the motor a light mist. I got in the car to drive, and the tach was sticking again. It likes to stick at 3000RPM and will only move if i drop or rev up or down ~1000 rpm (drop to 2K or accelerate to 4K). After a few mins, when there is some heat under the hood, the problem goes away. It only really happens when it's very cold (under 40 degrees) or raining/wet out.....or if i wash my motor. Anyway it's bugging me and i'd like to fix it. Are the crank position sensors responsible for the tach readings?? How can i test them? I do know where they are on the motor, but don't understand how they work. They look like 2 small black boxes with a single wire coming out.