recently, my civic started making this faint ticking noise, almost sounds like when you stick a card in a fan. its not constant, it only occurs when your foot is slightly touching the gas at certain RPMs, or at any RPM over 4k and then stops at 7k. also happens when i clutch and the load is taken off, and then when i release the clutch in the next gear. since its not constant, ive ruled out a spun bearing..could be wrong? i checked the heatshield for moving parts and found nothing. im at a loss of ideas, any help would be greatly appreciated