Feels like stalling, but doesn’t 2010 Ford focus

Ford Focus

100,400miles automatic
Car drives wonderful until I stop at a light. The idle rpm starts out good then starts to drop, then it vibrates to where it feels like stalling, but doesn’t. I put it in neutral and it’s fine. Car has new spark plugs and new throttle body. Not sure what is going on


Check Engine Light On? Any Codes present? What was the reason for installing the new throttle body?

I am thinking a vacuum leak if some kind from what you have stated the car is doing. This could be an external or internal leak. An internal leak would be from the EGR valve or IAC valve. Another thought could be some sticking fuel injectors. Any codes you may have would help pin point the issue area.