Spikehorn,
Here's a good article that talks about the DPFE Sensor and EGR valve. It's for the Ford Focus, but I think it provides a real good explanation of how they work and a posible diagnostics capability.
http://www.focushacks.com/printable.php?modid=80
In your case, excessive EGR flow could indicate that the EGR valve is stuck open.
__________________
Good Luck...
mj
'01 Ford Ranger 3.0 Super Cab, K&N Air, MaxFlow Exhaust, Oversize Tires

'93 Ford Taurus 3.0 (Ugh! What a MONEY PIT! Traded it in for the '01 Ranger)

'87 Ford Ranger 2.3 Super Cab (Owned it for 16 years until some clown t-boned me in it!)

'92 Ford Aerostar 3.0 (Gave it to Ex in Divorce Settlement) Hehe...
'74 Ford Maverick 250 ci (Great car! 110 mph on Autoban! Traded it in for the '87 Ranger)
'66 Ford Mustang 200 ci (Screwed up and SOLD IT!!)