One problem related to manifold/header/muffler/tail pipe has been reported for the 2000 Mazda 626. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2000 Mazda 626 based on all problems reported for the 2000 626.
Vehicle began to make pinging noise, that was only noticeable under heavy acceleration, thus causing me, the driver, to acclerate with gingerly. Approx. One day after the engine made pinging noise no matter how fast or slow the vehicle accelerated, eventually leading up to the following: the car was at a speed of approx 55-60 mph on the freeway, when all of a sudden the pinging got louder, the engine lost all power, a loud noise occured, something appeared to shoot from underneath the vehicle, and smoke began to pour from under the hood. After the vehicle was towed to a local service station, I was then told that an engine rod blew through the engine block, thus requiring a new engine. Approx 1 1/2 to 2 weeks prior an oil change was performed on the vehicle, and thereafter the car ran with no problems at all up until the pinging occurance. The vehicle is currently under manufacturer extended warrant, but has not been determined whether it covered under warrant at this point or not.