From another website...Differential Pressure Feedback EGR - it's basically like a MAP or a barometric pressure sensor for your EGR system - it's there to measure the flow of EGR, but it's very troublesome IMO.
The sensor should be either a black or metal box about the size of a large zippo lighter with two vacuum hoses attached to it near the firewall. The hoses should go to your EGR tube between your intake and your exhaust manifolds.
i have an accufab 75mm too. I'm going to try this, did it end up being the throttle body creating this issue then? and did it go away when you adjusted it? thanks
i deleted my whole EGR system, along with that piece.. that could probably be the problem?
I tried to adjust the throttle body blade, but i couldnt really adjust it. I'm going to try it again. It shows light all around the blade, evenly though.
Does the idle drop when the IAC electrical connector is disconnected? If so, by how much.
What is the value of the TP-MODE PID when this problem happens? If it's not "C/T", then look at binding throttle linkage, bad/weak return spring, or bad TPS.
What is the IAC duty percentage? Should be in the 40-60 percent range. If very low (<35%), this indicates too much air is passing the throttle body butterfly valves. There is either a vacuum leak or the TB idle set screw is too high.
Confirm there are no vacuum leaks where the EGR system has been removed.