Can anyone tell me if there is a factory service diagnostic tool available or where I would get one today? Is this something I would have to look around for? Also, how useful are they? Will they read all the actual parameters when the engine is running?

 

Last time I heard anything about the Mazda unit "if you have to ask, you can't afford it" applied. I think it costs close to US $20,000. To see what it does read the FSM - particularly the emissions section. It's used a lot there.
Oh, and I'm pretty sure they will not sell it to you unless you're a dealer .