When draining kitchen sink, water backs up the second sink, slow to go down. I checked the trap and the lines going to trap, all clear.

Have u run a snake from trap into wall?

I sink vented?

Chuck

Yes the sink is vented, and checked trap, and line going to wall is good.

Hi simmy and welcome to The Plumbing Page at AskMeHelpDesk.com

I checked the trap and the lines going to trap, all clear.
The next step would be to snake the line in the wall, Remove the "J" bend from the trap and send a snake up into the wall. You'll hit a bend about 8 in but once past that you'll only have 6 more feet to go. Flush with a sink full of hot water. Good luck, Tom