In my mind its not electronic. Forget the gauge (reading what boost you got), forget map sensor etc.. overboost will still happen if conditions allow & hence then throw a code in a normal engine (unless running something to disguise the actual psi from the ecu - as i do).
Back in the day with every mod i've done in place - pulling vac wastegate line off, allowed turbo to do what ever it likes boost pressure wise as there is no mechanical intervention to stop it on the 3.2. This would fire boost pressure skywards past 25 psi instantly on the way to who knows where?.
Wastegate isn't leaking as tested original one but since then a full new turbo fitted,
Exhaust completely free flowing as all new & bigger so no blockage,
Chip i have doesn't limit what max boost i get if anything should build boost with extra fuel available - but with chip off or on in the past 23 psi just fine - now 19 psi,
Intake free and clean,
Intercooler pipes checked & all OK but haven't tested core for a leak,
EGT blanking plate in from almost new so forget that path,
Both manifolds off dip stripped and replaced,
fuel filter replaced several times,
Engine boost needs pressured air from turbo and fuel that's all. No reason why i don't have air pressure - turbo is ready to go and indeed happy to give me 19 psi, so leaves fuel?
Really only things in the fuel line are; injectors & pump. This missing boost happened practically instantly so not slowly over time so in my mind not injectors getting worn out? Which leaves injector pump maybe?
The 19 psi manifold i have is solid, no wavering or pulsing and like i have said above, ute goes like a demon right now and i have no complaints but when i had 23 psi the thing was ballastic,
Luv to get that "Good Time" bac