2000 Dodge Stratus Unknown problem

I have had this car to 3 or 4 mechanics because of strange noises when idling at a stop sign. The first time it was a flap-flap-flap like a card on a bike tire. The second time it was a howling noise and the last time, it began a chattering, rattling. All noises stop after a short time--before I start off from the stop. A friend who is an expert mechanic is completely baffled and most garages don't even want to look unless you know what's wrong. I'm afraid to drive it for any distance because I don't want to break down on the road. (I"m a 72 year old grandma.) Can you help or do I have to get a different car? Could it be the water pump? A bearing? The universal joint, whatever that is. It always happens when I'm stopped and engine is idling.