when I am driving it idle normal but when I stop it idle high and if I drive it a kilometre it start raving high and low

This happens each time I drive my car. I have 268,911 miles on my car.

my car receives little gas. idling as it will go off.
while driving ejected black smoke and poor draft.
I'm afraid that he's broken air flow sensor.

Oil filter points and condensor

Petrol filter

I need to know what to do. I had the oil change and I also put this gas cleaner in the gas before filling it up. Can that be the problem, it was not doing that before

What is the average cost for the clutch to be repaired. The estimate I got was $800.00

Please I need probable cause or area to look at the problem. The engine Idle is very unstable sometimes it reach to 1500 rpm then later it goes down to 1000 or 900 rpm. i already adjust he throttle but still the same problem. no check engine light indicates.

the battery was replaced in the car and hooked up backwards, and the car will not start now