Troubleshooting tips wanted Seat Altea from 2010: Black smoke, jerky engine and starting difficulties

Hi guys, I really appreciate all your advice! After reading your messages, I made an appointment with my mechanic and asked him to take a look at it. It really was the mass airflow sensor that needed replacing and now my Seat is running like a dream! And yes, the cost of €250 was totally reasonable. Thank you very much for your help, you really saved me a lot of headaches and stress.

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Hey, I had a similar problem with my Seat Leon from 2013, which also involved black smoke and a bumpy engine. When I went to the garage, it turned out that something was wrong with the mass air flow sensor. Indeed it was. The jerking and the problems with starting were probably also due to this. All the best!

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Hey, thanks for your feedback! That's interesting, I hadn't considered the mass airflow sensor. Can you remember roughly what you paid for it? And have you noticed any other problems since then? Would really appreciate an update!

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Moin, after the visit to the mechanic, nothing more occurred. Regarding your question about the costs, it was indeed not cheap. The repair for the defective sensor cost me around €240. So I would advise you to have your car checked by a specialist.

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Hello there, so this high mileage could of course be related to the faulty mixture preparation. With 142,345 kilometers on the odometer, your Altea has seen quite a few roads! But I'm no expert, so it would be best to have your car checked in a workshop. If the problem really is the mass air flow sensor, I would advise you to check the other parts of the mixture preparation system as well. With such a high mileage, it's definitely worth it! It would be a shame to repair the mass air flow sensor now and then the next part breaks in a few months. It's annoying to have to pay for it now, but it's the better solution in the long term. Keep us posted and good luck!

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Motor indicator with fault code P21F400

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The fault code P21F400 is related to the exhaust after-treatment system. It could be due to a faulty Diesel Particulate Filter (DPF) or Exhaust Gas Recirculation (EGR) valve. It's best to have a professional mechanic inspect your vehicle to pinpoint the exact issue. Please keep us updated on the progress. Do you have any other questions or concerns?

Servus Can someone tell me what to do if the error message says: Bank 1 mixture adaptation additive too lean.

(Translated from German)

The error message you're seeing typically indicates that there's too much air and not enough fuel in your engine's air-fuel mixture. This could be due to a vacuum leak, a faulty mass air flow sensor, or a problem with the fuel injectors. Start by checking for any visible signs of a vacuum leak. If you can't find any, it might be best to have a professional mechanic inspect your vehicle. Please keep us updated on your progress. Do you have any other questions?