A little while ago I wanted to change the faucet in my bathroom. I bought new taps and it came with a pop-up drain cover so I changed that out and replaced an old chrome P-trap with plastic. The old sink setup was working fine - I just didn't like the taps. When I re-connected everything, the sink is draining temendously slowly. It can take up to an hour for a sink full of water to drain. All the pipes are new. I have taken the pipes apart several times and there is no clog. The drains were running fine before I changed the taps. I have no idea what the problem could be. I have put an auger through the system as far as I can get it to go and I can find no clogs. The toilet and the tub drain fine.

Could you leave on the taps and put the old metal stuff back in? The old P trap and stuff, nobody sees it, and if it worked before...

Sounds like you may have pushed the new trap to far into the wall and it is blocking the flow... try cutting a small amount off and see it that works.

Plumberman may have hit on the only answer there is outside of a stopper that's not set high enough. Pull the trap assembly out of the wall and cut the trap tail back so only a few inches go into the stubout. Reassemble and test. Drain better now? Good luck, Tom