If your Campro is IAFM(Integrated Air Fuel Module) version, after sometimes, you found annoying sound "tak..tak..tak.." from your engine bay. Its actually the sound of IAFM valve needle. The IAFM varies intake manifold which is control by engine vacuum, length to suit different engine conditions - a short runner length for high revs and a long and narrower runner length for low revs. The IAFM actually eliminates the torque dip which is well known for old Campro engines.