I have an '08 Civic Mugen and recently replaced my HID’s. Soon after I noticed a buzzing noise that gets louder as I accelerate.
Please help…
Disconnect the HID’s and see if the buzzing goes away. If it does it could be a weak alternator or the wrong HID’s. A good, independent mechanic can fix your problem quickly.
Maybe the buzzing is a rattling heat shield on the exhaust. You say this buzzing started “soon after” without saying how soon and an exhaust rattle can start at anytime.