It suddenly shut down when I am about to stop !

I think the real problem may be the Power Brake Assist. It has a large vacuum line running from the booster to the intake. If it is cracked or not attached, it will cause the engine to run poor and stall. If it is failing it will also be hard to stop car and cause the stall issue when you press on brakes.
A quick way to test it is to pump up brakes before you start it.
Keep your foot on the brake and start the car. The pedal should drop away under foot when the engine starts, but not all the way to the floor.
If it does not drop at all, it probably needs replacement.
From the symptoms you describe, this is more than likely the problem.

Then, if the problem still occurs after that is sorted out, I would look at is the Idle
Air Control Valve, IACV. It is located on the intake near the throttle body. Make sure that if it has a vacuum line that is is in good shape. You may have to clean it. If you do, it generally has coolant hoses running in and out of it. So, drain that bit out, remove it from intake and be careful of the diaphragm which some types have to actuate ports. It may also have an electrical connector. Check it for clean terminals and damaged wires. Make sure the diaphragm, if applicable, is in good shape without any breaks. To clean it, use brake cleaner and spray only in direction of intake, from IACV towards intake. Spraying pother way can worsen clogs. Do not spary a lot just fill ports and let it sit and then apply vacuum to tube to open diaphragm and clean through ports that you can see all the way through.

You are very welcome. Come back to us anytime and our Tech team, or myself if you need more help with this issue, is very willing and able to get you through any problem you might have.
Take care and let me know how it goes.

Dr. C