XC70 Jerking Acceleration

The symptoms you describe are consistent with a potential issue in the boost pressure regulation system. The whistling and hissing noises, coupled with the reduced engine power and jerking, strongly suggest a boost leak. Has there been any investigation into the intake manifold or the boost sensor itself? It would be useful to check live data from the boost pressure sensor to ascertain whether its readings are plausible under different engine loads.

Thanks for the quick response. I haven't had a chance to check the live data from the boost sensor yet. Where exactly is the boost sensor located on this model, and is there a way to check the cable or plug connection without specialized tools?

The boost pressure sensor on the 2011 XC70 gasoline engine is typically located on the intake manifold, often near the throttle body. A visual inspection of the cable and plug is possible to check for any obvious damage, corrosion, or loose connections. However, without diagnostic equipment, it's difficult to definitively rule out internal sensor malfunction or wiring issues. Given the symptoms and your findings, it would be prudent to have a workshop perform a thorough diagnosis to prevent potential consequential damage to the turbocharger.

Appreciate the detailed advice. I took it to the workshop, and you were spot on. It was a defective cable connection to the boost pressure sensor. They replaced the connector, and the total repair cost was 95€. Runs like new now. Thanks again!