1999 Taurus - EGR Fault Code (1400)

I am getting an EGR voltage out of range fault code (1400) on a 1999 Taurus with 3.0L 6 cylindar OHC engine. The car has around 150,000 miles.
I don't know if it is the EGR sensor or the EGR valve, but both parts are
pretty expensive. Also, it could be carbon build up from what I understand, but when I took off the hoses leading to the sensor, I did not notice any.
I figure I can replace both parts cheaper than I can pay someone to replace one of them. So the way I see it, it is worth the gamble that I can guess correctly as to what the problem is.
Anyone with lots of experience who can give me any pointers, or even just a good educated guess as to what is more likely the root problem?
Also, this fault code has been around for a little more than a year (almost as long as we had the car) and it seems that I remember it used to come up as a fault code 401. However, now only fault code 1400 comes up after having cleared it before.
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On Mon, 16 Aug 2004 20:32:03 -0400, "rrrowell"

I just got a similar trouble code on my 2001 taurus with the duratec engine. I checked the EGR valve for vacuum and it seemed to work fine. I went to the parts department of the Ford dealership and they told me that the differential feedback sensor was probably the cause of the problem. For $32 I replaced it and the car has no more codes. I find in general that the guys there are pretty good about what problems are caused by what part. I hope this helps. Richard
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