1999 Ford Taurus

Lean fuel condition could be caused by one of the following below:

1.Vacuum leaks
2.EGR and PCV valve.
3.Low fuel pressure.
4.Dirty fuel injectors.
5.Mass Air Flow Sensor.
6.Oxygen Sensor.

i replaced the egr valve, and gaskets, the regulator and the feedback still had lean bank one and two on my dohc 99 taurus se. took off the air hose and sprayed the map sensor and then took off the throttle body there was a chunk of carbon built up in the groove that i had to dislodge with screwdriver and clean out with throttle body cleaner. put it all back together so it eliminated some of the egr codes but still had the elusive bank one bank two lean codes. my mechanic took some carb cleaner and sprayed on the intake upper and lower and found the elusive vacuume leak there. quick replacement of gaskets, put in some plugs and wires and did the leaky valve cover gaskets that was leaking onto the exhaust manifod causing a horible stiink when i turned on the defroster during the winter. i changed the cabin filter and she runs pretty good
had some issues of same problem the egr hose was brittle and i had to buy a 7 dollar 5/32 egr hose and some 5/32 washer fluid hose as splice it back together she runs pretty good after clearing the codes of egr and o2 sensors and misfires. my mechanic says i need to do something about a clogged cat due to length of number 3 cylinder misfiring.