Welcome to 2CarPros.
Based on your description, it does sound like a vacuum leak. First, here is a link that shows how to test for a leak:
Next, there are two systems this came with. One is traditional the other is electronic. I'm not sure which you are dealing with. Pic 4 shows the standard type. If that is what you have, check for the vacuum leaks as I mentioned. Also, when you removed the EGR, did you confirm the port in the intake was free of carbon? It could be plugged.
Also, I attached a picture (pic 1) of the EGR system. I need you to check those specific hoses to confirm there are no leaks.
Next, on a linear design, the EGR function is controlled by the power-train control module (PCM) based on readings from other components. Pic 2 shows a schematic of how electrically it works. Picture 3 shows where the module is located. The module is what receives the signal from the PCM to open or close the EGR valve.
I need to know if the intake where it mounts was clean, was the gasket replaced, are there any vacuum leaks and any information you think may be helpful.
Take care and let me know what you find.
Images (Click to enlarge)
Saturday, May 11th, 2019 AT 8:36 PM