mine does the same and i've researched it. unless you running the right tuning on it at about 1.5k it'll have a camloop.... weird but it's there. no biggie. only does it when the trannies not engaged. when you start to go it stops. damn JDM ignition timing....rofl....but your good you we\won't blow up or anything i've been running mine now for about a year. and no problems. GL.