I took off and cleaned the p-trap and connecting pipes from the sink to the wall. I snaked the pipe in the wall approx 4 feet down. The sink drain pipe in the wall is about four feet to the toilet drain. I know this because I just re-did the basement last summer. The pipes connected to the toilet drain and tub drain are working fine. What happens is the p-trap fills up and the water backs up into the sink. The water in the p-trap is not going down the drain. When the water backs up into the sink it very slowly goes down. I even poured water into the wall pipe when the p-trap was off and the water went down without a problem.
Thanks

Is there a vent on the sink? This sink. Kitchen or bathroom? Regards, Tom

I think so. Do you mean an overflow drain in the sink? It is a bathroom sink.
I also did some more reseach on the website and found that some people had the same problem. They were told to cut the pipe from the wall back a bit. It doesn't look like this pipe is blocking the p-trap by eyeballing it though. Any other suggestions?
Thanks

By the way it is funny that you are asking about a vent. I feel like it is a scientific problem, i.e.. Air, gravity et al.

Please Help!
I have tried everything. I even poured a large amount of water down the pipe coming out of the wall. The water went down fine. There is no clog. I'm having trouble when the pvc pipe/p-trap is connected to the wall pipe and sink drain. I think it is a pressure problem.
Thanks

What is the difference between an overflow drain and a vent?

This is just so I can subscribe if you answer...

What is the difference between an overflow drain and a vent?
The overflow on a lavatory and bath tub are there to prevent the fixture from overflowing. The vent is there to relieve the suction caused by a fixture discharge as it drains. A overflow handles one fixture while a vent services the entire drainage system, Regards, Tom

By the way it is funny that you are asking about a vent. I feel like it is a scientific problem, i.e.. Air, gravity et al. oke,
Do you hear a gurgle or glub when the fixture drains? Let me know. Tom,