Seat Arosa Diesel Engine Power Loss

I think I know what you're talking about! I had a similar issue with my old Renault Megane. Check engine light, sluggish performance. Did you notice any change in fuel consumption? For me, it was a vacuum leak related to the pressure sensor. Made the engine run like it was choking. Does yours whistle a bit at idle? It could be a clue. I'm no expert, but it might be worth checking the sensor and its connections. Is the sensor properly seated? Are the car sensors clean? Just a thought.

You mentioned a vacuum leak. How did you diagnose that? What should I look for when checking the sensor connections? Any specific areas that are more prone to causing issues?

Vacuum leak was the culprit for me. It's hard to pinpoint without proper tools, but listen for hissing sounds around the intake manifold. As for the sensor connections, check for any loose wires or cracked hoses. If you can, wiggle the connector while the engine is running (carefully!) and see if the engine stumbles. Unless you're really comfortable working on cars, I'd recommend taking it to a workshop. A proper diagnosis will save you a lot of guesswork.

Just to let you know, the problem is fixed. It was a faulty intake manifold pressure sensor, like you thought. Cost about 235€ at the workshop, but the car is running smoothly now. Thanks for the help!