Make sure your base timing is correct with the motor warmed up, then adjust the idle screw on the throttle body. There should be a sealant that's applied all over the screw if it's never been monkeyed with, just scrape it all out with something sharp, then goop some silicone back over it with your finger when you're done adjusting it and it won't leak.

Check your timing again. One adjustment affects the other.