Lexus SC Engine Misfire

That sounds suspiciously like the issues I had with my old 2012 Opel Insignia. Rough running, stalling – classic symptoms of a coil failure. Have you had the fault codes read? It's important to pinpoint which coil is the culprit, as replacing them all can get expensive. A failing connection could also be the source of the problem. I would check the wiring harness.

Thanks for the insight! Yes, I have read the fault codes, and I get a misfire on cylinder 3. That points to the third ignition coil, or at least that's what I think. Could the connection to the coil really cause all these symptoms?

Absolutely, a bad connection can mimic a failing coil perfectly. The engine control unit relies on a stable signal from the coil. An intermittent or weak signal due to a corroded or loose connection will definitely trigger misfires and rough running. However, given the fault code you retrieved, you should visit a workshop and have your car looked at by a professional. They have measurement tools that can test the ignition coil under load, and that will give you certainty.

Thanks so much for the help! I took it to the workshop, and you were spot on. It was a defective ignition coil and a corroded connector to the coil on cylinder 3. Cost me 95€ to replace. Runs like new again!