Renault SM3 Poor Start Fuel Consumption

Hey, I drive an SM3 too! Sounds familiar. I had similar symptoms - rough starts and the engine occasionally cutting out at lights. Have you checked for any misfires?

Misfires, no. I haven't checked that yet. How did you determine that was the issue and how did you fix it?

I didn't determine it myself, honestly. The symptoms sounded bad enough that I took it straight to a workshop. They ran some diagnostics and confirmed it was the injection system. Best to get it checked properly.

Thanks for the advice! I took it to a shop, and you were right. Turns out it was a defective injection nozzle, likely due to it being dirty. Had it replaced, cost me 515€. Runs much better now!