Vel Satis Jerking Whistling Stalling

That sounds frustrating! I had almost the EXACT same symptoms with my old Opel Insignia – jerking, whistling, the whole shebang. Check engine light was on too. Turned out to be a boost leak somewhere in the turbo system. The whistling was the air escaping under pressure. Have you checked all the hoses and connections around the intake manifold and the turbo itself? A loose clamp or a cracked hose could be the culprit. Is there any chance you have access to a smoke machine? That could help you identify the location of the leak. Or perhaps it's an issue with the boost sensor. What's the code that the CEL is throwing?

Cheers for the quick reply! Yeah, it's driving me nuts. I don't have a smoke machine unfortunately. When you say boost leak, was it obvious where it was coming from on your Insignia, or was it a pain to track down? You mentioned the sensor; I am still suspicious about the boost pressure sensor itself. Did you have any issues with that?

For me it was hard to track down. I even took it to a local mechanic as I was worried about messing up the turbo system. He found a small crack in one of the hoses going to the intercooler. Regarding the sensor, the mechanic told me it was ok. If the cable and plug connection of the sensor is defective as you initially said, then it's definitely a good starting point. It might be a simple fix if you can replace or repair that yourself. Otherwise, I would suggest taking it to a trusted workshop to avoid any further damage.

Thanks for sharing your experience and the great advice! I really appreciate it. I took your advice and went to the workshop. It turned out to be exactly what I suspected - the boost pressure sensor. The cable connection was indeed defective. They replaced the sensor and the connector, and the total repair cost was 95€. Now it runs like new again!