What are the symptoms of a bad crankshaft sensor on my Mazda RX8
When when I try to start the vehicle the engine just spins over but no cranking is present replace the starter already I did get under the vehicle and observed the crankshaft sensor that's currently present it was gummed out with black thick sludge on the sensor part as well as the housing I cleaned it but still no cranking available when turning the key over just a spinning engine

 

Thats a weird question. Unstable idle, stalling, etc, but many different problems can cause those.
Want to rewind to what problems youre having?

 

I had an eccentric shaft position sensor fail in my 04 after it had sat in storage for the winter a couple years back. It gave me a crank no start condition. I found the car had no spark and no injector pulse. The crazy thing is that it passed a resistance test. Would have needed an oscilloscope to look at the wave form to confirm that it was bad. I replaced it on a suggestion from another forum member, as I thought that if the resistance were in spec, it would be ok and would pass a waveform test as well. I was wrong. I replaced it with a known good ESS I had and the car has been running great since.

 

The resistance can still be in spec and it can fail the waveform pattern test.