I found that the vacuum feed that goes to the EGR Solenoid was broken. Fixed it easily enough. Reset the computer and all of the Readiness Monitors have completed -- come to the Ready state -- except the CAT monitor.

Is the EGR system part of the CAT monitor? If yes, then I have more work to do on the EGR, if no then I have trouble in the CAT system somewhere. I replaced the DPFE before I found the vacuum leak, but the new DPFE has a voltage that I think might be out of range, but the spec sheet that came with it said not to worry. I worry.

 

What engine?

 

No, the cat monitor is separate from EGR. Be patient, it may take a few days of driving before all monitors are ready.

 

It's the 4.6L V8. Sorry.

The hold-out monitor finally came to Ready.

Next project,
Getting the gear selector out of P.

 

RELATED BUT DIFFERENT
In the corner of the engine bay, behind the battery, there is a vacuum connection that goes to several places, one of the tiny hoses that comes off of this connection has a check valve on it, and the flap to the life support system goes to it. If the ventilation system shifts to Defrost all by itself when the engine load changes, look at the hoses in this area, specifically the really small one. The small hose on my truck broke and I fixed it with a plastic T. The leak is not large enough to make the engine run poorly or to trip a lean code, but it does cause the ventilation system to shift gears from whatever it is set on to Defrost.