So I was driving my 04 rx8 the other day to work when it just stalled very hard and rpms dropped to zero. It turns over but won't start. All ignition coils are good and fuel is good. Fuses good. I believe it could be the ESS but I don't exactly know what ESS does. Or it could be bad compression. Doing a compression test tomorrow. Am I heading in the right path or any other suggestions? I tried to deflood it too and still nothing. Would an ESS cause a car to turn over but not fire?

 

A failed ESS would do that, but those things don't just up and die. It's the rotary equivalent of a crank position sensor: tells the computer where the engine is in its rotation.

Leading causes of sudden stop: catastrophic apex seal failure, failed fuel pump, failed ignition. Only the apex seals have no warning signs before the sudden stop. See how the compression test comes out. Examine your spark plugs for strange deposits while you have them out.

 

If you tested the coils and they all work...ie you have spark it isn't the ESS. When it fails you have NO spark or injectors.