Peugeot 607 Mixture Preparation Error

Alright, Peugeot gurus, I'm scratching my head here. My 2010 Peugeot 607 (gasoline engine) is throwing a 'mixture preparation error'. She's got 169462 km on the clock. I'm getting reduced power, the check engine light is on, rough running, and a nasty jerking when I accelerate. Sometimes, it even stalls at idle. I've checked the usual suspects - MAF sensor seems okay, no obvious vacuum leaks. I'm leaning towards a fuel injection issue, maybe a dodgy injector? Anyone seen this before?

4 comment(s)

Sounds familiar. I had similar symptoms on my old Saab 9-3 – although it was a diesel. 'Mixture preparation error' is vague, but those symptoms point towards fueling issues. On the Saab, it turned out to be a faulty injector. Before you go ripping things apart, have you checked the oxygen sensor readings? A bad O2 sensor can mess with the fuel trim and cause similar problems. What about the spark plugs? Are they fouled?

Good shout on the O2 sensor. I'll check the readings. As for the plugs, they're relatively new, but I'll pull them and have a look. When your Saab had the injector issue, was it constant, or intermittent? And did you notice any difference in fuel consumption?

On the Saab, the injector issue started intermittently, then became constant. Fuel consumption definitely went up. The rough running and stalling got progressively worse. Honestly, after checking the O2 sensor and spark plugs, I'd recommend getting the injectors professionally tested. Could save you a lot of time and money in the long run. Otherwise, you will be in the dark.

Thanks. I appreciate the insight. I had a feeling it was pointing that way. Took it to my workshop and you were spot on – defective injector. All fixed now. Cost me 515€ including parts and labor, but she's running like a dream again. Cheers!

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