Okay just making sure but I found one I think, we are talking about the ecm on the firewall on passenger side yes?
That's the PCM. ECM is on the block on the driver side, down under intake horn/VP area.
Im not sure I may have missed it, but have you checked fuel pressure? also since I believe I read when you took your edge off it got worse, and if I remember right edges change timing and computer perameters maybe your ECM needs rest, could also be sometime internal, I say pull the head and just check who knows, if anything its quick easy and doesnt cost anything really and can eliminate many things, I really dont think its your VP though.
could also be your alternator acting up. wouldn't hurt to clean off your batt posts as well. seems like your chasing an electrical issue not a hard part issue.