Quest rough cold start

I had similar symptoms on my Quest: rough cold starts and poor running until warm. Have you checked the fuel rail pressure? Could be a faulty injector not delivering enough fuel when the engine is cold.

Thanks for the quick reply! I haven't checked the fuel rail pressure yet, but that's a good idea. Was it definitely the cold start injector on yours, or something else in the fuel system? Any idea how much that cost to fix?

I wasn't able to diagnose it myself and took it to a workshop. They confirmed it was the injection valve/injector; the invoice mentioned 'poor engine running in the cold start phase' and 'vehicle start poorly'. The repair cost me around 515€.

Thanks so much for the info! Sounds like I'm headed to the shop too. I appreciate you sharing your experience!