Lean Condition Code
 

My son has a 98 Contour with about 75k actual miles. It has a 2.0 Zetec engine with auto trans. Recently the car died on him and set a code in the computer that says there is a lean condition. Our mechanic has had the car for a couple of weeks. He has checked everything relative to a lean condition and can find nothing wrong. The care runs great! He is driving it around with his computer attached trying to make it set the code again. He says there are no vacuum leaks and the CO2 sensor is working within its proper range. Has anyone else had this problem and what was the cause?
Thanks

Does the code come back after clearing?

Can you remember what the specific code number was?

Lot's of things can cause a lean condition

Another approach may help here. If for example you had a defective injector causing a rich condition as seen by the oxygen sensor and corrected by the computer by reducing injector pulse width thereby resulting in a lean condition. If nothing else just looking for a cause for a lean condition may only be half of the possible cause/ solution.