Seat Ibiza Check Engine Light

Sounds like a vacuum leak. I had a similar issue with my Ibiza. The check engine light was on, and the engine was stalling frequently. Check your vacuum hoses, especially those connected to the air intake manifold. They tend to crack and cause all sorts of problems.

Thanks for the tip. Where exactly should I be looking for these vacuum hoses? Is it something I can check myself without special tools?

Yes, it's likely to be the culprit. The hoses run all over the engine bay, so follow them from the air intake. Check for any cracks or loose connections. You could try to wiggle them around while the engine is running and listen for changes in the engine note. I'd recommend taking it to a workshop though if you're not confident messing around with the air intake system.

I took it to a garage. They found a defective hose connection from the pump to the valve, just as you suggested. Repair was 175€. All good now. Thanks again for your help.