XC90 Hybrid power loss and stalling

Sounds familiar! I've got an XC90 too, though not a hybrid. Had something similar happen a while back. Check engine, power loss, the works. Did you happen to notice any difference in how it sounds when accelerating, like a whooshing sound? Have you checked the intercooler pipes for any cracks or loose connections?

A whooshing sound, yeah, kinda like that. Intercooler pipes, huh? Where exactly are those located? And would that really cause all these problems – stalling and everything?

The intercooler pipes run from the turbo to the intercooler and then to the engine. If one of those pipes has a leak, you'll lose boost pressure, which explains the power loss, whistling, and hissing. Stalling could be related if the engine's not getting the right air/fuel mixture. I ended up taking mine to a shop; turned out the wastegate valve was defective. Cost me around 860€ to get it fixed.

Wastegate valve... got it! Thanks a bunch for the insight! I'll get it checked out ASAP. Just got the car back from the workshop, wastegate valve was the problem. Exactly 860€, just like you said! Thanks again!