Micra diesel poor starting high consumption

That sounds like a problem I had with my Micra, though mine's gasoline. Did you check the emissions? Poor starting and stalling could point to that, but also higher fuel consumption can happen for a lot of reasons. Have you had the car inspected recently?

I haven't had the emissions checked specifically, but the car passed its general inspection six months ago. Could a dirty injection valve cause these symptoms? I suspect that could be the issue. Would you recommend a fuel additive, or is a more thorough cleaning or even replacement necessary?

A fuel additive might help temporarily, but with those symptoms, and if the car hasn't been running perfectly for a while, I would say that a proper cleaning by a workshop will be necessary. I had similar issues and a valve replacement set me back 515€. It’s probably best to get it checked professionally before it causes further damage.

I appreciate your advice. It seems prudent to consult a workshop as you suggest. Given the potential severity and cost implications, a professional diagnosis and repair are warranted. Thanks for sharing your experience; it has been most helpful in guiding my decision.