Outside trap when left opened no backup in kitchen sink - can I just leave it opened - had line snaked a month ago - Thanks AB

I am not sure what "outside trap" means, but I will assume you meant to say "outside clean out."

If that's the case, than pipe is still blocked and now, you are dumping grey water into your lawn. You still need to clean that pipe. Insert snake through outside clean out, run it through few times, flush it with lots of water - and you should be back in business

Hope that helps

Milo

I am with Milo, tell us about this "outside trap".

Assuming you mean that you have a clean out for the kitchen drain, close it up. Fill sink with water. Open sink drain. If sink does not empty, go outside and remove clean out plug. If water comes out clean out you have a blocked drain. Snake the line again.
If water does not come out the clean out but sink drains, I would suspect that you have a blocked vent pipe.
Do you have an AAV for the kitchen drain or do you have a vent pipe going through the roof?