I just bought a running 2004 mazda 6s 3.0. The had run it out of oil due to timing case leak. He put new oil in and it runs but has knock and no power. It sound like its from heads not sure though. I was thinking spun cam and bad lifter. Any advice on known issues or personal experience would be great. Also best price on rebuild kits. Thanks

 

Most common issue with hi mileage old 3.0 litres is the fact that oil over time can clog the pre-cats, some catalytic pre-cat particles can go back through the EGR system and back in to intake.
No oil also could lead to connecting rod failure.
You really need to check pre-cats as well as the engine!
Pre-cats available thru Magnaflow: The Official Site of MagnaFlow Exhaust Products - Exhaust Systems For Trucks, Suv's, American Muscle, Diesel, & Sport Compact Vehicles

 

http://m.youtube.com/watch?feature=y...ure%3Dyoutu.be

My car sounds identical to this one

 

Does pre cat failure means i need to replace motor or just put headers on

 

Depends where knocking sound is, that needs to be figured out.
A compression test would be helpful as well!