sounds like pulsating - like fades in and out right ? Do you have any other problems associated with the noise? Can you hear it with the hood open in idle ?
I would clean the throttle body and check the hoses and other attachments in the area. Check the plastic covers and valve cover - tighten the nuts etc. clean the area as much as you can while checking the area for loose parts etc. Also check vacuum hoses and confirm that they are firm and in good direction/order.. Any thing in the area could contribute to the sounds .. Good luck
I would clean the throttle body and check the hoses and other attachments in the area. Check the plastic covers and valve cover - tighten the nuts etc. clean the area as much as you can while checking the area for loose parts etc. Also check vacuum hoses and confirm that they are firm and in good direction/order.. Any thing in the area could contribute to the sounds .. Good luck