Seat Altea Diesel Reduced Engine Power

Sounds familiar. I had a similar issue with my Seat, a Leon. Kept getting a fault code and the engine felt choked. Did the diagnostic code point to anything specific Have you checked the usual suspects, like air flow or fuel delivery

The diagnostic code was kinda vague, something about 'performance issues'. How did you eventually sort yours Did you have to replace any major components

That 'performance issues' code is a pain because it could be anything. In my case, it turned out some previous owner had tried to get clever with the ECU and installed a cheap chip tuning thingy. It messed everything up. I'd recommend getting it checked out by a proper mechanic who knows their way around vehicle diagnostics. They should be able to pinpoint it. If it's the tuning, they can probably flash it back to the original settings.

Big thanks for the heads up I took it to a local garage, turns out it was indeed some dodgy chip tuning the previous owner had done. They flashed it back to the stock settings and it's running like a champ again. Cost me 180€ but worth it to get rid of that annoying dashboard light