Mackpro

Hopefully you can help me out. 

Boost pressure wont build over 30lbs on aset 460. Do see the green wire has some wear through but i wrapped in electrical tape for time being. 

But the reason im asking is i have a 3-2 code with if you push mode and reset at same time on dash is 5022-02 m128. Code means engine speed sensor but which one. I just replace both 2months ago and i only have one spare and hoping its not the bellhousing bc its a bitch. Also can it feel like truck is in limp mode.

Still kinda new at understanding mack.but im some mechanically inclined