Please post the full DTC codes. There are 1000's and they each have a story to tell.
Exactly which EGR component are we talking about? EGR valve, EGR vacuum solenoid, or DPFE?
OBTW, if the line keeps popping off is it really a surprise it runs like crap? Are you sure you have the correct lines for the application? If you have used common vacuum lines on the EGR DPFE sensor, those lines can not handle the high heat of exhaust gases.
As a long shot, consider that if the cats are blocked, this would create excessive back pressure in the exhaust. I could see a case where the excessive back pressure would blow the flexible lines off of the DPFE sensor. Also note that the two lines from the DPFE sensor are DIFFERENT sizes.
The lines to/from the DPFE sensor are difficult to inspect due to firewall clearence issues. Perform a through visual inspection looking for split lines. Use a mirror and a bright light.
Consider using a set of replacement lines from Ford. They will cost more $$, but will be correct for the EGR application (DPFE sensor to EGR bypass line only).