if it is coming from your motor, may be a lifter that is ticking. when your oil pressure drops it would be circulating less back up to them. Mine is doing a slightly same tick. it is more in the transmission area. im thinkin that it may be in my transfer case, more specifically the drive chain. just a few places to start, depending on where its coming from. as dumb as it sounds, try to feel for it. if you feel it in the hood, probably more in the motor. if you feel it in the shift knob, more in your transmission.