I have a 2004 Honda Civic Hybrid with a manual transmission. A 'chirping' noise started about a month ago and I cannot find it. It only happens under load. It won't make the noise when I idle and/or rev the engine. It won't make the noise when I first start it in the morning and drive down the street. It starts once the engine is warm. It's definitely a mechanical noise. It happens when I'm in gear and stepping on the gas pedal. Speed of the car has nothing to do with it. The chirp will get faster as the RPM's increase, however. If I'm going 70 MPH and take my foot off of the gas pedal the chirp goes away. Push on the gas pedal and the chirp happens. I've replaced the Serpentine belt and the belt tightener with no luck. It sounds like it's coming from the center of the engine but obviously I cannot tell exactly because it only happens when I'm driving down the road. Really hoping someone can help!