01 Explorer Sport Trac EGR Insufficient Flow

I have replaced everything on the EGR system, have cleaned the MAF and other things with Total intake system cleaner and I can still not get the check engine light to go off and the code is always EGR insufficient flow. What else do I need to do? I need help really bad because I can’t pass the mandatory emissions testing.

I forgot to mention that this is a 4.0 L V6 with 160,000 miles on it. Nothing else is wrong with it and this isn’t even causing any problem. Maybe just a slight rough idle is all.

The DPFE sensor is a common problem with this system or the tubes leading to and from the sensor.