Hello. I have a 1992 Ford Bronco 5.8L 4x4. At about 2000 rpm the engine feels like its surging. Plus, for this?

sounds like a powertrain mangment concern. look at things like your throttle position sensor and your m airflow. a vac leak would show up as a rough idle and i dont really understand how soapy water helps find it. i get it on a tire as it makes it bubble but vac sucks not blows. your not gonna see bubbles from it. anyways if the last poster could explain i would be more then willing to listen. good luck