Vauxhall Vectra Rich Running Issue

I had similar issues with my Vectra. Symptoms sound like a classic rich mixture problem. Have you checked the oxygen sensor? It plays a vital role in measuring the oxygen content in the exhaust gases, which the ECU uses to adjust the air-fuel ratio. A faulty oxygen sensor can send incorrect data to the ECU, leading it to inject too much fuel. How is the air-fuel ratio?

Thanks. I haven't tested the oxygen sensor directly, but I considered it. When you had similar symptoms with your Vectra, did the issue stem specifically from the oxygen sensor, or were there other contributing factors? Can you elaborate on air-fuel ratio?

In my instance, the faulty injector was to blame. The oxygen sensor, while important, didn't resolve the issue. Given all of the variables that can cause this, I would go to the workshop before replacing parts at random. They can test your injectors properly.

Following a thorough diagnostic assessment, it was determined that a defective fuel injector was responsible for the rich running condition. The faulty injector has now been replaced, at a total cost of 515€, which has resolved the issue. Thanks again for your guidance.