Car jerks when going down a hill and loss of power

[Zikernieks]

Hey.

So I all of a sudden experienced these problems - while on cruise control and going down a hill my car (Volvo v70 2010 2.0D) starts to jerk and also it has significantly less power, also there was a whining noise. Upon further inspection, I found a vacuum hose that had a massive tear in it, so I replaced it. After starting the engine there still was a whining noise coming from the bottom of the engine. Took it to a mechanic and it turned out the hose from the turbo had come loose and it was losing boost, so he fixed it. Problem fixed I thought. Drove it home, no jerking apparent, but the power was a little weird. A couple of days after taking it home, the jerking resumed and there's still a significant loss of power. Has anyone had a problem like this before? Could it be a sensor that has gone bad?

Thank you.