Welcome to CEG!
A few things to think about:
As the catalytic converters age, they tend to block exhaust flow causing increased exhaust pressure even if they still work. This reduces power and efficiency gradually over time.
Unless severe, only checking exhaust pressure will tell you if this problem exists.
The EGR passages also clog with carbon and soot over time. The missing exhaust gasses are replaced with like ammounts of fresh air and fuel. The ignition timing becomes reduced because of pre-ignition (often called pinging) and fuel economy and power suffer again. With a similar result, the DPFE sensor can go bad either reducing the EGR flow itself or lying about the ammount of clogging and keeping the CEL from lighting.
You are about due for new plug wires.
Vacuum leaks occur around the intake manifolds when the O-rings begin to crack. A 96 is due for gasket replacement.
The rubber hose from the upper intake to the PCV valve eventually goes bad and is often missed because of it's placement under the throttle body.
The MAF needs periodic cleaning, apparently unbeknownst to FORD.
Luck!
