Puma 2.2 - whistling under load

Good Evening all, hope you are well.

My 90 pickup is whistling under load.

Performance is still strong, reading forums it could be hoses, gasket, waste gate sticking, boost leak, hose clamp off the bottom of the intercooler.

Any other suggestions,

I have attached a picture, showing a heavy pile of soot, yet I’m right in thinking manifold and turbo are on the other side of the truck right?

You can rule out the waste gate - it isn't got one. Any of the others you listed are possibles, and add a leak in the intercooler - the plastic end boxes can separate from the ally core, look at the metal tags which keep the boxes attached to the core. Faults I have experienced include the intercooler as above, split in hose between the turbo and the intercooler (this was a service recall when the original 3-part item was changed for a one part item), and hole in the rubber hose at the throttle body. This last item is hard to see as it hides behind a birds nest of other hoses. I also had a sensor which unscrewed itself from the exhaust pipe where it exits the DPF, that caused a whistle but no loss of power (whereas all the other faults affected the power). There are (I think) three sensors on the exhaust / DPF to look at. And a temperature sensor and MAP sensor on the hoses between the intercooler and throttle body which might have gone loose.