Insignia Manifold Pressure Sensor Issue

Sounds exactly like what happened with my Insignia too! Exact same symptoms. Have you checked for any hissing sounds around the intake? It could be a split hose or a dodgy gasket somewhere. Like a bathtub draining when it shouldn't be! What mileage are you on?

Good shout on the hissing, I'll give it a listen. I'm sitting at 143563 km. But where exactly should I be focusing my search for that vacuum leak? Any specific areas that are notorious on these engines?

Definitely check all the hoses connected to the intake manifold, especially the smaller vacuum lines. They tend to get brittle and crack. If you aren't sure, I'd take it to a decent garage to smoke test it and replace the sensor. I had to cough up 235€ to get mine sorted.

Cheers for the advice! Gave it a look myself, couldn't pinpoint the leak. Bit the bullet and took it to the shop. Turns out it was a vacuum leak at the manifold, causing the sensor to read wrong. New sensor, leak fixed, and she's purring again. Thanks again!