Lexus SC engine stalls at idle

I had almost the exact same symptoms on my SC. Have you checked your fuel volume regulator? It might be a similar cause!

Thanks, that’s helpful. Where is it located, and is it something I can fix myself, or should I take it to a professional?

The fuel volume regulator is connected to the high pressure fuel pump which could cause this issue. Given the symptoms you described, you should definitely have a workshop check it out with their diagnostic tools.

Thank you, that confirms my suspicion. I took the car to the workshop, and they confirmed the high pressure pump was defective, which damaged the fuel volume regulator. The eventual repair cost came to 1510€. I will keep an eye on fuel efficiency and misfires in the future.