Hi, Around late December my kitchen sink started to drain real slow, so I got a snake and snaked out he lines. Pulled back the usual "black goo" and everything seemed to be fine. Then this weekend I doing A little yard work and notice water coming out from behind the siding. Upon further inspection, I found an old cast iron tee fitting had been leaking, pin size hole in it. I pulled it out and replaced it with new fittings, but the sink is slow again. Not as slow as it was before the snake. It seems to bubble and gurgle which kind of makes me think It might be the vent line clogged. I just wanted some other opinions before I climb up on the roof. Any help would be greatly appreciated. Thank you.