Venue engine jerking whistling

Those symptoms do point towards a potential boost leak somewhere in your air intake system. The jerking and power loss suggest the engine isn't getting the proper air/fuel mixture due to that leak. Think of it like trying to drink from a straw with a hole in it – you're not getting the full amount you need. Check the hoses connected to your intake manifold and turbocharger. It could also be a faulty boost pressure sensor sending incorrect readings to the ECU. Have you checked the cable or plug connection of the boost sensor? A loose or damaged connection can cause all sorts of issues.

Where exactly is the boost pressure sensor located? And how can I check the cable or plug connection?

The boost pressure sensor is often found on the intake manifold, or somewhere along the air intake tubing between the turbocharger/intercooler and the engine. It's there to monitor the air pressure entering the engine. Visually inspect the sensor and the plug that connects to it. Look for any obvious damage – cracked plastic, corrosion, or loose wires. Disconnect the plug (engine off, of course) and check the pins inside for corrosion or bending. A multimeter can be useful for testing the continuity of the wires leading to the sensor, but that gets a bit more involved. Given the symptoms, getting it properly diagnosed at a workshop may save you time in the long run.

OK. Thank you for the advice. I took it to the workshop, and the cable connection on the boost pressure sensor was indeed defective. Repair cost me 95€.