One problem related to gas recirculation valve (egr valve) has been reported for the 1997 Ford Taurus. The most recently reported issues are listed below.
The "service engine soon" light came on and was diagnosed at a local auto parts store with code 402 that showed excessive flow in the egr system. I removed the egr valve and tube from the engine and inspected the components. The egr valve was extremely clean and did not show any leakage through the valve when it was closed. The tube leading from the exhaust manifold to the egr valve was also extremely clean. The battery was disconnected to reset the indicator light. Two days later, the indicator light illuminated again. The vehicle was taken to clarke Ford in hudson, ohio for repairs. The vehicle was tested by a mechanic who found the same results. I was charged for two labor hours for replacement of the dpfe sensor and trouble shooting. I told the dealer that I wished to keep the old parts. When I reviewed the old part with the mechanic, excessive corrosion was present in the hose of the sensor. The mechanic and service writer informed me that Ford no longer manufactures the sensor from metal and the replacement is plastic to prevent the corrosion. The service writer proceeded to show me the print out that displayed the replacement information. I had been to clarke Ford on two consecutive days before this automobile was serviced to schedule the appointments for service on two vehicles and to drop the vehicles for servicing. While I was speaking with the service writer, no less than 5 other customers received the same news of a bad dpfe sensor. The service writer informed me that this failure was very common. I feel that this situation needs further investigation since the problem appears to be so widespread and has a new style replacement part to fix the corrosion problem.