One problem related to transmission sensor has been reported for the 1997 Mazda 626. The most recently reported issues are listed below.
1997 Mazda 626lx 2. 0l. Had the o/d light come on twice. Then about a year later the vehicle started to shift hard/slip. Inspected valve body of the transmission & fluid, everything was ok. Did a transmission flush anyway. Did not have any codes in the system until 6 months down the line. Was for the transmission range sensor. Installed a new one & vehicle operated normal. Since I put a new range sensor in the vehicle, o/d light has come on about 5 times but no abnormal driving condition yet. Only notice it when driving on the highway with cruise control engage. Also have the vehicle rough idling. Found no vacuum leaks, pcv valve is new, spark plugs & wire set new. Fuel additive added every 6 months. Fuel injectors are operating. Ticking noise occurs every once & awhile from engine. Do know that the transmission in these cars are not capable of handle the engine. The fact that a Ford probe small transmission was put into the Mazda. It needs an transmission oil cooler to be install but was not a recall issue, only a bulletin that must be paid for by the customer. Exact day this started to happen is unknown. A new proper transmission should be introduce as a recall for these cars.