I have several pics to show Detroit DD series owners here. First, is the IMAP sensor located under a protective bracket just downstream of the throttle housing. Three 13mm bolts and the bracket is off (piece of cake). Then two 10mm bolts and that's it. I used a screwdriver to GENTLY pry on the sensor and removed it with cable attached. I was surprised, no soot buildup to speak of so I sprayed with a little carb clean and dusted it off with a fine wire brush then reinstalled.

Next I went after the EGR DeltaP sensor. You have to remove the cable to get it off so be careful. YouTube it or break it. Cleaning the sensor was no problem at all...a couple of shots of carb cleaner and a small cable tie to get in between the cracks and she was clean. The other side though was a little more involved. As you can see in one of the pictures, I used a cable tie to clean the soot out of the ports in the venturi. One side the tie went all the way through. The other side did not. I blew on it and it was plugged solid. I decided to remove the entire venturi and clean the entire thing. 3-13mm bolts on one end, a 13mm bolt on the bracket and two 13mm bolts in front of the engine and she was mine. I used a "pick set" I got from Harbor Freight to jam up inside that port hole and twisted around until all the soot was clear. I blew on it and it was free. Then took a cable tie and cleaned it the rest of the way. After that it was just a matter of replacing the venturi and the bolts, then put the bracket back on top of the IMAP sensor and it was done.
Side notes, no gaskets were needed. Also, I found it best to loosen the hose clamps on the rubber hose attaching the two sections together as it was much easier to manipulate both halves. One other side note, next time I'm probably going to use tip cleaners to cleanout the DeltaP sensor. They're much sturdier and flexible as well.