It means your clutch is dragging. It sounds like the clutch friction disks are worn and its dragging and making the chattering noise
Idling is what your car is doing when it is just sitting somewhere running. As soon as you press on the gas it is no longer idling. Your idle speed is the number of RPMs your engine runs at when you are idling.
Vaccuum leak somewhere
I assume that this is a petrol engined Mondeo The Mondeo's idle speed is controled by a sealed air system Most erattic idling problems are caused by an air leak somewhere in the system.
It has a leak in the Cooling System Somewhere, It might have a cracked Head or a Blown gasket
my idling on my 2001 ford focus is not idling correct, tried to adjust idling but there is no screw or way to adjust why?
Chances are, particularly if this is an automatic transmission, you are low on tranny fluid. To check this, the engine needs to be at normal operating temperature and idling. Checking tranny fluid when the engine is cold and not idling will give a false reading, indicating that it is full ...
I think I'd check for a loose, cracked or missing vacuum hose somewhere under the hood. FriPilot
Because even idling engines use fuel.
I sat in my car in the driveway with the car idling, waiting for the kids to come out.
change the mass air flow senser
water in the fuel can cause an idling motor to sputter and/or die.
Effectively all the fuel that it burns while idling. You are getting 0 miles per gallon while idling.