About a week ago, I had my stereo all the way down when I heard a slight clicking noise as i began to accelerate from a stop. It sounds like it is occuring around the left back wheel. It starts off slow, but as i speed up it gets faster until i reach about 15mph then it goes away completely. The noise sounds almost like something is dragging but there isn't. All around the same time this noise started my truck began idling a little harder while merging onto highways as well. Dont know if it is connected with one another. Just had a very expensive tune up about 3 months ago. Please let me know what you guys think. Thanks

 

could possibly be a U-joint when the go bad they click.. not saying that could be it but a good place to start

 

or a brake pad ticking.

 

i would check your drivetrain, brake included, mya be brakes, could be something like a wire wrapped around your driveshaft... and over 15 mph you just dont here it...

take your drums off, check those...

hang your head ( and a passengers head) out the windows to here it better at a low speed ( like in your driveway, or on a very unused road, do this safe) and tell which wheel its coming from