2004 Ford Taurus

Engine Performance problem
2004 Ford Taurus 6 cyl Two Wheel Drive Automatic 175K miles

I have a 2003 Taurus.

I have been battling various emissions issues for the past two months. SO far the tally is FOUR oxygen sensors and several chewed vacuum lines (courtesy of warmth seeking rodents).

The dreaded " Check Engine" light still remains and the codes reported are P0401 & P0174.

According to my maintenance manual those are respectively 'EGR Insufficient Flow Detected' AND 'System Adaptive Fuel too lean (Bank 2)'.

Another symptom is that the car seems to run fine at high speed i.E. The highway but when idling it idles roughly and sometimes will stall.

According to my maintenance manual the EGR system shouldn't really be a factor at idling time.

Can anyone point me in a direction that could lead to my solving this issue without hemorrhaging more cash?

Otter River, MA
April 27, 2010.

Actually, I would remove the EGR and check it to make sure it is carbon free and working properly. As far as the lean mixture, are you sure you got all the vacuum leaks?

Well my mechanic did a smoke test and seems to be of the mind that he got all the leaks. There's only so many places the vac lines go.

As for the EGR valve I removed it myself and ran a brush over both orifices there was no huge build-up of carbon, AND while putting a vacuum on the vac port I could see the 'pintle' travel upwards which I took to mean that valve is doing its job. What I really can't see is the valve seat for all I know it could be completely fouled BUT I doubt that would cause an insufficient EGR flow indication. Logic suggests such a condition would a cause excessive EGR flow, No?

Apr 27, 2010.
Did he check engine vacuum hoses? Usually a smoke test is for the EVAP system.