Three problems related to catalytic convertor have been reported for the 1999 Mazda 626. The most recently reported issues are listed below.
Sluggish performance and "check engine" light illuminated which resulted in my bringing the automobile into my mechanic for servcing - diagnostic code (2nd time for this code) resulted in a replacement of 2 oxygen sensors and the catalytic converter at a cost of > $750. The first time this code appeared, the mechanic tuned up the engine, which cost $300.
1999 Mazda 626 -complete transmission failure in March,2003. Replaced with rebuilt transmission for $2048. 00 - Jan-2006 - complete transmission failure again. I have also replaced catalytic converter twice, within one years time.
The catalytic converter malfunctioned. Also, torque converter became defective, resulting in major transmission problems.