Had the motor go on my 04 Mazda 6S at 128k do to bad pcv. No check engine light, over heating, power failure or any signs of engine failure outside slight knock in motor. Notice that oil was frequently needing replaced yet no signs of leaking. Took to mechanic who informed me that it was the 3rd one he has seen in last 5 years with the same exact issue. Bad pcv leading to lack of oil pressure and ultimately leading to the breaking of rod. Moral of the story.. periodic replacement of 15$ part :) On to my Dodge Ram 1500!

This is the first major problem I have had. My mazda6 will crank then shuts back off. You can't put your foot on the gas pedal to try to make the car run, it won't stay running for sh*t.

Update from Jul 29, 2012: Had to take it to Mazda dealer. It took them a few days to fix the problem. Come to find out somebody had tampered with the fuses underneath the hood. It fried my ems box. The problem is fixed but not a cheap problem,but it probably could have been a lot worse than what it was.