So still no improvements, but I did notice something else that might help: when I first start my truck, or first come to a stop at a light, the truck idles ok for about 10-15secs. After that it starts shaking and that continues to worsen the longer I sit. There is also heavy pinging/tapping. Because of that, I feel it is still a build up of (or lack of) air/fuel. I’m going to take the EGR valve off and see if I can blow air through it without vacuum, maybe it’s not closing all the way? The valve does hold vacuum, so it looks like the pintle is good. I’ve also read of bad ignition coils causing similar issues?
Dusty, I think I can get my hands on a compression tester also if you’re still thinking I should check compression.
So moving down my list of possibilities...I checked the voltage on my DPFE #1 circuit and I'm getting 0.68V at (cold) idle and 0.9V at 4.5 inHg when the engine stalls. Does the truck need to be warmed up to run this test?