I talked to many dealers and shops, and someone said that the early 2003/04 6.0L ICP at the back of the block (on the HPOP) and the newer style ICP (2004-2006) on the passenger valve cover weren't compatible.

Someone posted a YouTube video showing the slight voltage difference between the two. The earlier ICP putting out somewhere near 0.1V less, across the 0-5V spread.

So, yesterday, I removed the degass bottle and the FICM, replaced my dead 2003 ICP with a new 2005 ICP, new IPR, new EBP sensor, new connectors for ICP, IPR, & turbo. The newer ICP is a 15/16" I think, and the older ICP is 1-1/16" i think. I'm not in the garage (to verify the sizes), but I bought standard (not impact) deep sockets from Sears, then cut an inch off of them to accommodate the ICP. I bought an IPR socket on amazon for $50 or so.

I used a small piece of 1/2 hose that fit inside the ICP connector, and black electrical taped the hose to the sensor. I used it to get the ICP threaded into the hole. THen pulled the tube and the tape off. Torqued it to 12Nm, Then threaded the IPR in and torqued it to ~50Nm. The electical connector was facing downward, then read online that it will spin on the IPR body, so I loosened the socket off of the IPR not (body) and spun the IPR body til the connector was at 12 noon, straight up.

Anyway, After putting everything back together, it started right up, no problem. I finished the installation of all the new Autometer digital gauges, with new sensors all over the place. It's nice to have it all back together.

The difference I see is that the Autometer HPOP Guage (tapped off of the ICP wires) is that is now reads a little more true. At idle, the HPOP is ~550psi, but the Autometer gauge would read ~400. Now it reads about 500psi./ Although it is slightly different, it seems that the HPOP gauge was made for the newer ICP's. Not a big deal, but the new sensor works perfectly, And I have heard that the newer gauge is built better and lasts longer.

Again, a local shop just told me that the ICP's were NOT compatible, right before doing this job, but I went ahead according to the YoutTube video, and tried it, and it works perfectly. I got some special heat "boots" for spark plugs, and used them when I put all new connectors on, to completely protect the sensors and wires from the heat from the Up-pipes. I also used the thick ICP sensor heat protection sleeve, and all the other OEM stuff that was on the wires.