car runs rough when you apply gas

When I start the car I run fin when I push down on the gas petal and give more gas it start's running bad. Like it's missing or has bad gas. Also there is a hose that runs from the transmission up to a what looks like oval container the hose is plugged up to the bottom of the container but the hose that run's on top is hooked up to the top of the container but it not hook up to anything on the other. End the hose curve's on the end where it is not hooked up where does it go I can't find where it needs to be hooked up to.please help thanks.