Volvo D4 compressorturbo

"I have a 2008 37-ft with twin

"I have a 2008 37-ft with twin D4-300/sterndrives and have done 250 hours on them. The problem arose last July (160 hrs) on the starboard engine (the port engine performs perfectly).
IMPORTANT: The following problem appears most of the times, but not always. Roughly 70%.
Pushing down the levers, the compressor (supercharger?) will not start until 2000 rpm, instead of 1700 rpm, that it used to – and the other engine still does, resulting to overall delayed – and struggling – plane.
Pushing the levers further, while the port engine easily reaches 2900 rpm for optimal cruising speed (27 knts) or 3400 rpm at WOT (33 knts), the starboard engine will not go above 2400 rpm, while its turbo pressure gauge reading is considerably lower than the one of the port engine.
My Volvo mechanic suggested and carried out change of compressor belt, which did not help. His VODIA diagnostic showed no malfunction. The propellers seem OK.
Opinions here and there suggest various things, from ventilation and air filter to electronics and EVC software.
Any suggestions or similarities?
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"Your problem is in sensor tha

"Your problem is in sensor that are measuring boost pressure and manifold temperature. On VODIA your mechanic can not see any fault because sensor measuring vrong value but not out of the range. What does it mean?? Manifold temp. is 36 but your sensor will show 55 or biger!!! That will see your mechanic on VODIA, and also to compare with value on good engine. Also say to your mechanic that , he will find bulletin about this problem on VPPN site. You and your mechanic will solve the problem for one hour (in warranty).
And also, because of wrong value of manifold temp.
ECU gives less fuel to your engine and turbo pressure is lower."

"Thanks for your suggestion. I

"Thanks for your suggestion. Indeed, my mechanic suggested lately - last week when I took him for a ride - that we should change the turbo pressure sensor and I was very upset that he did not say so earlier. Now I have lifted the boat out of the water for winterization and servicing and I will launch it back in a couple of months, so I will get back to you with confirmation. Many thanks again."