GTP making weird noise?!?

i have a 98 gtp with 146k on it. Im at a red light and notice there is a rattling or some type of clanking coming from my car in the alternator area. I step on the gas and the noise goes away as i pick up speed. Im familiar with the sc coupler rattling issue and am pretty sure it isnt that, as i replaced it bout a year ago. (the noise Sounds like someones putting a plastic sheet in a fan). Anywho the car runs just fine, no overheating or anything, just makes this noise when im Not stepping on the gas. Any guesses??!

There is several things that it could be. It is possible to be your tensioner pulley, water pump, air conditioner pulley, or maybe the power steering pump, or the alternator.

anyway of narrowing that down? far as i know the ac is not really having problems, i did replace the tensioner pulley, pulley only, bout a month ago, but i replaced it with a 3.5" pulley instead of the the stock 3" which hasnt given me problems, or least i dont think it did.....

anyway of narrowing that down? far as i know the ac is not really having problems, i did replace the tensioner pulley, pulley only, bout a month ago, but i replaced it with a 3.5" pulley instead of the the stock 3" which hasnt given me problems, or least i dont think it did.....
I would take off the serp belt and start it for a few seconds to see if it is related to the pulleys. Then I would grab each pulley firmly and try to wiggle it to see if it is loose on its shaft. My wife's van had a noise similar to the one you are having and it turned out to be the water pump. I could move the water pump pulley in ways it was not supposed to be moving. It was not leaking.

anyway of narrowing that down? far as i know the ac is not really having problems, i did replace the tensioner pulley, pulley only, bout a month ago, but i replaced it with a 3.5" pulley instead of the the stock 3" which hasnt given me problems, or least i dont think it did.....
I would take off the serp belt and start it for a few seconds to see if it is related to the pulleys. Then I would grab each pulley firmly and try to wiggle it to see if it is loose on its shaft. My wife's van had a noise similar to the one you are having and it turned out to be the water pump. I could move the water pump pulley in ways it was not supposed to be moving. It was not leaking. Also examine the belt for damage.

It could also be the balancer. The rubber in them rotts away and eventually get so bad they can make a sound almost like a bad connecting rod knock.

Mine is starting to get bad, I can hear it clank sometimes when I turn the car off. It hasn't been a big issue, so I am going to run with it untill it gets worse.

Have a look at your balancer. Do you see rubber missing or cracks?

my 99 gtp is making a rattle at low rpm but its the tensioner for the supercharger, not the tensioner pulley.

ya that same sound happened to me and it turned out to be my alternator.. i broke a bearing, and bent the rotor inside... maybe its that. good luck finding/fixing it though!

Sometimes when you get an oil change the crappy mechanic will tweek/hit the bottom engine cover when removing the oil filter. Sometimes when this happens this cover will come into contact with the power steering or crank pulley. Remove the passenger front wheel and inspect the wheel well. Next I would apply belt dressing to the pulley assemblies. Next check for the clicking around the bank 1 area. Did you ever install a high ratio rocker kit?

take a hose put one end to your ear and move it around it will help so you can pin point the noise but DONOT PUT IT UP AGAINST MOVING PARTS you will not like the out come if you do.

The way i diagnosed my rattle was with a Mechanic's Stethoscope. All you have to do is probe the engine with the needle till you find whats making the noise.