Seat Toledo diesel engine performance issue

Your situation sounds rather familiar. I own a Seat Toledo myself, with a diesel engine, and I experienced similar symptoms a while back. The engine light was on, and the car felt sluggish, especially when trying to accelerate. There was also a noticeable jerking. Did you happen to notice any unusual hissing sounds when accelerating? That was a key symptom for me. I am not a mechanic but I think you might have the same problem with the manifold flap. Hope this helps.

Thank you for the quick reply. Indeed, I also experience a loud hissing sound when accelerating, which I should have mentioned. Could you please clarify if the engine misfire and reduced power were constant, or did they occur intermittently?

Yes, the engine misfire was constant for me once the problem developed. Given the hissing sound you are experiencing, it does strongly suggest an issue with the intake manifold flap. It might be best to have a workshop take a look. They can properly diagnose the problem. Ignoring it can result in more significant damage to the engine in the long run.

I appreciate you sharing your experience. It seems my suspicions were correct. I have taken the car to a workshop, and they confirmed it’s the intake manifold flap control. The repair, including parts and labor, will be around 465€. Thanks again for your help.