I have a 2003 Chevy venture. Mine was doing this and it ended up being the wheel bearing.
Check coolant level Cooling fan working? Dirt or clogged radiator? Defective radiator cap?
As the vehicle sits idling the driveshaft is not rotating.
Yes, when idling and driving.
It could be the belt tensioner or perhaps a tension transferral from a faulty harmonic balancer.
I have an 04 Venture that did the same thing. Turned out to be the Engine mounts, apparently it is really common. Since i have gotten them replaced i haven't heard the noise or had a single problem.
Probably wheel bearings or wheels are unbalanced
Really need more info for an answer to be correct. Is this a car? If so, the clicking could be numerous things from low oil level to a broken valve guide.
It depends on how long you are idling, or how fast you are going. If you know you are going to be idling for a long time, it's best just to put your car in park.
Car emissions can be reduced by reducing idling time and by driving at a moderate highway speed when possible. Driving too fast and idling are both wasteful in terms of fuel, and increase the vehicle's emissions.
Check your electric fan operation and coolant level. If the fan is not working, temp will increase at idle and will decrease when air moves across the radiator while moving.
It's a 1997 Tahoe
You need to check the operation of the radiator fan.