Hello today, I have a 93 civic del sol that I just got but have known the other owner for a long time and it started revving up like a vacuum line leek. It's revving between 2000&2500 RPM's and when it started I was talking about it with a coworker and he told me it's a sensor under the intake manifold but for the life of me I don't remember what it was called. I'm hoping someone would know what the sensor is