Peugeot 307 Engine Running Rich

My 2003 Peugeot 307 with a gasoline engine (189406 km) seems to be running too rich. I've got reduced engine power, a check engine light, rough running, increased fuel consumption, and jerking during acceleration. I suspect the injection system. Any insights?

4 comment(s)

Sounds like a fueling issue. Have you checked your spark plugs recently? A rich condition can foul them up pretty quickly. Also, what's the condition of your oxygen sensor? A faulty O2 sensor can definitely throw off the air-fuel ratio. Do you have any way to check the live data from the ECU?

Thanks. I haven't checked the spark plugs yet, but they're on my list. Regarding the oxygen sensor, is there a reliable way to test it without replacing it? And how do I read the live data from the ECU?

You can test the O2 sensor with a multimeter, checking its voltage output, but it’s not always conclusive without proper diagnostic tools. As for ECU data, you'll need an OBD2 scanner that can read live engine parameters. Considering your symptoms and mileage, and without access to specific tools, it might be wise to have a workshop check the fuel injectors. A defective injector could be the root cause.

I appreciate the advice. I took the Peugeot to a workshop. The diagnosis confirmed that one of the fuel injectors was defective. The repair, including parts and labor, cost 515€. Thanks again for pointing me in the right direction.

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