Skoda Roomster Engine Running Rich

Reduced engine power, rough running, and increased fuel consumption certainly point towards a fueling issue. The check engine light is also a key indicator. Have you checked the spark plugs recently? A rich running condition can quickly foul them. It would also be useful to know what the diagnostic code is that triggered the check engine light. That will narrow down the possibilities significantly. Also, are there any unusual smells from the exhaust, such as a strong fuel odor? An engine running too rich throws off the air-fuel ratio. Is the intake manifold free of any cracks or leaks?

Thank you for your response. I have not checked the spark plugs yet, but I will do so. Regarding the diagnostic code, I will have to get that read. Is it possible to check the intake manifold myself, or is that a job for a professional?

Based on the symptoms and your description, a defective fuel injector is a very plausible cause. The diagnostic code will confirm this, but the symptoms are certainly indicative. You can inspect the intake manifold for obvious cracks or loose connections, but a proper diagnosis often requires specialized equipment like a smoke tester. Given the potential for misdiagnosis and further complications, and especially considering the symptoms, I would recommend taking it to a trusted workshop for a proper diagnosis and repair. Running too rich for an extended period can damage the catalytic converter, which is even more expensive to replace. So, it is better to address the problem sooner rather than later.

Just to let you know, the workshop confirmed a faulty fuel injector. All four were replaced, and the car is running smoothly again. The bill was 515€ and fuel economy seems normal. Thanks for the help.