I installed a new vanity and Corian sink recently and it has drained slowly ever since. The new vanity is a little wider so the pipe dropping down from the sink is offset about a 1/2" from the p trap and the pipe above it. I used a connector to tie the 2 pipes together and while not perfectly straight vertically it does not leak. The pipe dropping from the sink is plastic. It goes to a straight steel (I assume) pipe rising from the
p-trap. There was never a drainage problem prior to this swap. The shower and toilet drain fine. They all tie to the same drain pipe and are vented from the same vent pipe. I tried to re-use as much as I could from the existing system. when you tirn the sink on you can hear that the pipe is filling and the sink full in 20 seconds or so. When the sink is draining there are alot of small bubbles rising from drain. I have dissassembled most or the pipes and was able to snake into the drop behind the wall. There are no clogs at all.
My guess is that it is the offset in the pipe creating the problem?

I hope someone can help.