Suggest you goto Autozone and purchase a $15 Manual, it has hundreds of pictures, details of install, removal, testing and function of alot of parts. It should suffice for a "home mechanic".

The DPFE (metal if OEM, Black plastic if it has been replaced, is located on the drivers side of the engine on my 99 4.6L EXP, is 3 in long, 2 in tall and .5 in thick), has 2 fuel line type hoses on one end and a cable harness.

The EGR Solenoid is a black 2 in tall cylinder, 1.5 in diameter, with 2 vacuum lines and a cable harness.

The EGR Valve is a 3 in metal cylinder, 1 in tall, with 1 in diameter connections with 4 bolts, and have a vac connection on the top.

The manual suggests ways to test each component, in logical order...

I had a DPFE problem on my 99 Taurus, and changed out parts with my Exp, to confirm my suspicion of a faulty DPFE.... NOTE the DPFE on a 99 Taurus is very hard to get to as compared to the EXPY....