juergenschubert10

Seat Altea engine running rough

Alright, I'm having some trouble with my 2006 Seat Altea. It's a gasoline engine with about 196083 km on the clock. The engine light is on, and it's running rough, plus there's a noticeable exhaust leak and a strong exhaust smell. I'm thinking it might be related to the exhaust treatment system. I've checked for obvious exhaust leaks, but haven't found anything major. Could a faulty EGR valve cause these symptoms? Or am I looking at something more serious, like a catalytic converter issue?

4 comment(s)

That sounds suspiciously like a lambda sensor issue. I had similar problems with my Seat Altea – not sure what year yours is, but I bet the exhaust system is similar. Engine light, rough idle, the whole shebang. Have you checked the sensor readings with an OBD scanner? Could also be an exhaust leak affecting the sensor readings, but you'd probably hear that.

Lambda sensor... Okay, interesting. When you say 'similar problems', was it definitely the lambda sensor that fixed it for you? And did you have an exhaust smell too? I've got a strong exhaust smell which I didn't mention. I also read something about DEF fluid and NOx sensors, but I don't know if that's relevant for a 2006 gasoline engine.

Yes, for me it was the lambda sensor. The exhaust smell was definitely there, quite pungent. DEF fluid and NOx sensors are more common on diesel engines, so you can probably rule that out. An exhaust leak itself can definitely throw off the lambda sensor readings and cause the engine to run poorly. Given the symptoms, my advice would be to get it checked out at a workshop. They can do a proper diagnostic and pinpoint the exact cause before you start throwing parts at it.

Thanks for the input. I took it to a local mechanic. Turned out it was a defective lambda sensor as you suspected, causing the exhaust leak and rough running. New sensor fitted and the engine light is gone. Cost me 375€. Appreciate the help.

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