Engine noise slight clinking noise from rear of engine on the pulley end only on slow idle.

The technique I always used to identify where such a noise was coming from was to use a very long screwdriver (2 feet long), while the engine is running. CAREFULLY touch the screwdriver end to each pulley or other object under the hood, and put your ear to the handle. The device making the noise will become very clear.

It could be AC pump/clutch, alternator, water pump, power steering pump, etc.

Jack the vehicle up by the pumpkin and use kickstand to support. Turn the wheel back and forth and you d should be able to isolate. It sounds like a gear in reared or wheel bearing

look at your idler pulley since the ac clutch runs on the serpintine belt its moving alot faster the berings are prob bad in it takes 10 minutes to take off and 17 dollars to replace n another ten but if you take it off spin it in your hand if its rubbing n stopping fast(should spen fast like a skateboard wheel) then its bad that could be all it good luck hope this helps

big end bearings( lower engine rod bearings to confuse) knock at idle and get louder with rpm
if the noise changes with rpm and you are hearing it near the ac compressor then it could be the ac pulley bearing
test if it is the compressor by listening and then turning the ac off the pulley will still spin but the compressor stops
if the noise remains , replace the pulley bearings

Sure its not coming from the rear end? They can also make a noise when you let off the throttle.

sounds like a pulley or bearing is noisy first remove drive belt and run engine if noise is gone problem is a bearing attatched to by hand spin and feel for rough or gritty feel chech all pulleys most common is adjuster or idler cant tell by feel goto parts store but a stethescope hearing tool run motor CAREFULLY listen to each area a pulley drives on try that first

Check the idler pulley. Does the noise happen when the A/C is on?

could be an idler puller for your serpentine belt your car has a timing chain unless it is a V6. use a long screwdriver 2ft as a stethascope to hear what is making noise. you must put tip of screwdriver on attachment bolt head of the pulley with engine running. dont get into the belt!

Replace the axle tie bar bushes.They have worn out,

most likely a belt tensioner or pulley take some penetrating oil and spray the center of each pulley one at a time if the noise stops you got your bad pulley if not take the belts off the motor and spin everything by hand to feel or hear any grinding noises if you still don't feel anything run the motor (not for more then a minute) with the belts off and if the noise is still apparent your timing belt needs to be checked right away! it may be on its way out and if that goes your motor is toast good luck and please rate -jeff