Ive got a 2011 chevy impala that just started making a ticking noise when your on the accelerator i dont hear it at idle. I assumed an exhaust leak so i took it to my buddy who has a car lift and looked underneath to find to no sign of a leak anywhere and honestly once it was up in the air the sound was gone, i even got in it on the lift and revved it and no sound. Soon as i pulled out the garage tho it was still there ticking away. Im at a loss im worried its my motor but it sounds like its coming from underneath the car not the engine. Any ideas?