How long is your crank position sensors lasting? My original lasted 175K miles. The first replacement lasted 3K, took it back under warranty and that one lasted 5K miles (aftermarket parts). Took it back and got money back. When these went bad, the truck wouldn't start at all. Bought one from Cummins. It has lasted almost 25K miles and is starting to throw the P0336 code and the tach goes to zero. If at idle the engine sometimes will stumble when the tach goes to zero. If off idle it will not stumble, tach just goes to zero. Doesn't appear even Cummins replacement units are any good.