Lexus SC rough running and stalling

My 2007 Lexus SC with a gasoline engine is having some serious issues. It's got about 232536 km on it. The check engine light is on, and the engine is running really rough. I've noticed a significant reduction in power, especially when accelerating – it feels like the car is jerking. Sometimes it even stalls when I'm idling. I suspect it might be related to mixture preparation. I was thinking of cleaning the throttle body or maybe checking the mass airflow sensor. Could it be a rich mixture problem affecting the air-fuel ratio, or maybe an oxygen sensor issue?

4 comment(s)

I also own a Lexus SC and experienced similar symptoms. Reduced power, rough running, and stalling at idle point towards mixture preparation problems. Have you scanned the car for any specific error codes? That would provide a clue. In my case, the error code indicated a problem with one of the fuel injectors.

Thanks for the quick reply! Yes, I did scan it, and it's showing a mixture preparation error. You mentioned fuel injectors – was it a specific injector, and how did you diagnose that?

The error code pointed to a specific injector. A mechanic can perform tests, such as checking the resistance of the injector coils, or testing the spray pattern to confirm that it is the injector. Given your symptoms and the error code, I recommend visiting a trusted workshop. The repair will likely cost around 515€.

Thanks a lot for the advice! I took it to my mechanic, and you were spot on – it was a defective injector. Replaced it, and now it's running like a dream. Appreciate the help!

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