i think i may have the same problem except mine does it when its just idling, i hear it the most when i first start up my car. but even after its been drivin i still hear it, if i have no music on and the windows shut i can still hear it too. its a clicking sound that just keeps going and going but its not too loud. my mechanic told me its just the vavles and its normal but i know that, i think i need a vavle adjustment too. if thats what i need how much does that cost to have done?