2009 Ford F350 6.4L powerstroke 4x4 Auto

  
I've been chasing bugs and windmills on my company truck, to save a buck and learn some new stuff in the process, for a few days now. Started off with a p0675 (open circuit on gp#5), a plugged up MAP and a VGT actuator that wouldn't cycle on KOEO (even with the glow plug harness detached to isolate the open circuit) along with a noticeable lack of power and some rough shifts. Also the actuator wasn't opening up when it was supposed to and creating too much exhaust back pressure till it would pop and dump. Live data showed that the VGTDC and the VGT\_MES were within .2 percent at most. MAP to EBP was averaging around 15.1psi and 17.9psi respectively. So something was holding back the PCM from telling the veins to open.

  
I cleaned the map, replaced the glow plug and harness since it was in pretty rough shape and the plug ohm'd out around 8.5. Tested all the others on that bank just to be certain. Turns out they were all old and all autolite, so I pulled the lot of them and swapped in some NGKs and did the same for the drivers side along with a new harness. Wanted to be certain that there wasn't any unexpected leach that would throw off the PCM.

  
From there I started the checks on the VGT. Started with taking off the linkage and checking the veins. The lever moved smooth as silk, so I hooked it back up. Checked incoming power and ground and noticed the voltage was down so I load tested the batteries. They were just over 5 years old, failed the test and due for replacement, so I did. Thinking that maybe the low voltage upset the PCM during its start up cycle checks. No dice. I then ran a diagnostic KOEO and it cycled without issue. So I used a manual override and it ran from top to bottom while the truck was idling without issue.

  
Time for some more live data. Everything seemed fine. The VGT was opening and closing with the load and spooling up more power than before without any noticeable lag, but it still felt off. Like it was hitting a ceiling before it could reach the top of the powerband. So I added the MAF to the line up and noticed that it was reading 1.37 lb/min at KOEO and was maxing out at 86.69 lb/min. I cleaned it and no change. I then unplugged it and took it out for a test drive. All the scopes showed it was doing what it was supposed to do when the system goes to the dead MAF protocol. Now the new MAF is on the way and I am praying that this the end of my woes. (for now)

I'm not one to throw parts that aren't justified at a rig, though I must admit that I am quite intimidated by this particular system due to all the handshakes it needs just to think straight. I'd like to believe that I had the proper sense to address each gremlin with a thorough check. Aside from all the other glow plugs, that's just a prejudice earned from working on rigs that grenaded because of autolite spark plugs going to pieces. With any luck I'll be performing all the ridiculous laundry list of steps for all the systems to relearn after clearing the KAM.

In the end I was just hoping for advice on if I have handled everything well enough so far and if there is anything that I have missed or suggestions to check with my scopes.

I'm happy to provide any additional data that y'all might know to be pertinent. 

The 6.4 PowerHeadache Blues