I picked up my first Tacoma, a 2010 regular cab 4x4, in late October. It's a 4cyl with manual trans. Over the past few weeks I have been noticing a gradually increasing droning sound at speeds roughly between 60 to 68 MPH. The sound can be mild at times or fairly deep with a very slight vibration. It is speed related and only occurs when I touch the gas and while in gear. There has to be a load. If I rev the engine in neutral at these speeds, no droning. Of course the dealership couldn't hear anything. Any ideas???
Thanks in advance!