Crankshaft Ventilation System?

When the head gasket starts to leak it can do so in a small way which is what you have described. Also, if the car engine is not run often and it never gets hot it will do this as well. Here are two guides to help confirm the issue. If the head gasket is okay please start a new thread for the stalling issue.

https://www.2carpros.com/articles/recognizing-the-symptoms-understanding-a-blown-head-gasket-in-your-vehicle

and

https://www.2carpros.com/articles/head-gasket-blown-test

Please go over these guides and get back to us.