Finally solved my hesitation problem on my 95 Contour 4 cyl. After fixing a check engine light and rough running I still had a very bad hesitation problem with an intermittent check engine light (Code 172 - lean mixture detected at O2 sensor bank one). A Ford mechanic friend of mine suggested I remove the Mass Airflow Sensor and very carefully clean the sensor wires with a Q-tip and rubbing alcohol or metal parts cleaner. I used the alcohol and then cleared the codes and reassembled. This seems to have corrected the problem. He suggested cleaning the sensor rather than replacing it since the sensor costs around $125! The sensor has two very small resistor wires that get dirty and contaminated. They sense less air than what is actually pass them when they are dirty. Hope this will work for others too. Good luck!
