@PissedOffMandaP The vent shouldn't be low. It vents sewer gas. You would know if it was low, you'd smell it. Not having a vent, or blocked vent would explain a lot of your issues.
@LizzyStarrrdust I don't know, but if you figure it out let me know. I've been the smartest uneducated guy in the room for years and I can't shake that feeling.