DISCLAIMER: I don't think this will work if you still have the EBPV(exhaust back pressure valve) still plugged in and functioning off the PCM, as that needs to read EBP and not boost. My truck has the EBPV unplugged and will soon be deleted so its not an issue.
A common issue on these 7.3's is the EBP(exhaust back pressure) tube and sensor will get clogged up with soot. Generally that means there is a leak in the sensor allowing the soot to travel up the tube, but i'd gurantee that every 7.3 built will have this issue at some point. So there are write-ups out there on how to remove the tube and either clean it, or replace it completely with a new stainless tube or whatever you want to use. But still, most of these will eventually leak and get clogged. So then again you get to fight it and clean it, and it becomes a PITA.
Or if your truck is like mine, where the tube has never been touched in 200k miles living in the rust belt, it will just twist or kink when you try removing it which means it has to be replaced. Well i have a scangauge so i can keep an eye on EBP, and noticed that shortly after installing my injectors my tube plugged up tight, and gave wacky readings. I cleaned the sensor and since then it just sits at 15psi, which is atmosphere. Thats been 7 months, 10k miles. Throughout that time i've been complaining about sloppy shifts and other trans related issues, and keep coming back to a clogged EBP tube can be part of the problem. So today i said enough is enough, and tackled it.
What I did:
I've seen it talked about indirectly on some different forums, so i figured i'd try tieing the EBP sensor into the MAP line. By doing that you are giving the sensor boost pressure, which for the most part is close to drive pressure. It also eliminates the chance of a tube or sensor clogging with soot in the future. So pretty much its a hassle-free solution. I also know that i read around for a while trying to find more about doing this, but i never found any info on it out there. So i figured i'd through together a write-up.
What you need:
1/4" barbed T
1/4" barbed to 1/8" female
1/4" rubber hose rated to 40psi, pretty much fuel or fuel injection line
Something to cut the rubber hose.
How I did it:
To install it you cut the MAP line where you want, insert the T, add on the new hose and run it out towards the EBP sensor. Then simply cut it where you want it, slide in the barbed fitting, hook up the sensor, and your done. Took me all of 5 minutes to do it, including the time it took me to find something to cut the hose with. Only thing i have left to do is get 4 clamps to throw on the barbed fittings so they don't come loose and leak.
Made a short little trip around the block and noticed an immediate difference in how the shifts felt, they feel crisper and more solid now that the EBP sensor is actually getting a reading. Pretty much the same results as replacing the line at a fraction of the cost, and i'll never have to touch it again.
Here are some pics, i can get some clear ones if needed, just gotta dig out my actual camera.
Overall its extremely simple, but i ran into issues finding the fitting i needed. To tap into the MAP line you need a T, which you can find anywhere. But to hook the sensor up to the 1/4" hose you need a 1/4" barbed to 1/8" female thread nipple. I tried several auto stores as well as Lowes and Home Depot, nobody had one. So at Napa we ended up using a 1/4" barbed to 1/8" male fitting, with a 1/8" threaded female coupler which gave me what i needed.