If your brake pedal is stiff and it stalls when you apply the brakes it sounds like the diaphram in you brake booster may be ruptured. A problem in the idle speed control system or transmission is the usual cause of this symptom.

Engine Stalls Dies When Hitting The Brakes Chevrolet Beretta
Engine stalls when braking. If it doesnt stall then its time for a new booster. If your egr valve is clogged dirty or defective it can cause your car to stall idle erratically or sputter depending on whether it is stuck open or closed. The engine runs normally otherwise. If it was a high float level it would be the rear bowl. If it does then either we are dealing with an engine vacuum issue or it could be related to a ground issue. If the engine runs poorly you should address that symptom first.
Thus causing the same thing as an intake manifold leak. Lower it till you have to bounce the car slightly to get gas out of the sight plug hole. Do what steve said and pull the vacuum line to the booster and cap it off and see if it still stalls. One way the car stalls is if there is a leak in the brake booster either by a blockage of the vacuum hose or. If the booster rubber diaphragm or system check valve are damaged this will provide an unwanted path for the engine vacuum to leak out. When the actuator malfunctions the engine gets no signal for idling speed and stops working.
I will help with the signal lights once i determine what is happening with the stalling. The engine stalls when coming to a stop or on deceleration. Why does a car stall when you brake. The brake system is composed of the disk brakes in the front end andor rear of the vehicle that connects. Ive seen a bad brake booster leak vacuum when the brakes were applied and almost killing the motor. Just for a test try unhooking the power brake vacuum line and plugging it.
Your torque converter has a lock up feature to improve gas mileageif you stop very suddenly sometimes you can beat the computer and bring the car to a stop with the converter locked which will stall the enginenormally the converter unlocks as you brake to a stop allowing the engine to idle. Some common reasons for motor vehicle stalls include. Clogged or restricted egr valve. 274 0 0 0. An empty gas tank a fuel mixture that isnt rich enough this is usually the cause of cold stalling and intermittent stalling a faulty fuel pump alternator or egr valve a dead battery a dirty air filter thats preventing good airflow low fuel. If you are sitting with the vehicle running and in neutral does it stall if you press the brakes.