[shorod]

Going off of memory here, but if my recall is correct, that code is also commonly associated with a faulty or mis-hosed DPFE sensor (aka EGR position sensor). The DPFE sensor was also a common failure item on Fords of that vintage. You might search the forum for "P0172" (note that it's a zero, not an 'o') or "DPFE" to find more common issues for the P0172 or details on the DPFE respectively.

-Rod