It maybe fuel line related, as it only happens to me when I keep my tank at low levels. I use a good fuel injection cleaner and take easy for awhile, once i to replace my fuel filter. But this is just a guess.
A leak in the brake booster is one common reason why a car would stall or hesitate when the brakes are pushed. There could also be an obstruction in the brake line.
No the can go faster downhill or uphill
Does your car have overdrive? Does it stall when going uphill? If you answered yes to these it is possible that your transmission kick down isn't working.The kickdown basically detects when the car becomes under load and shifts the transmission down a gear.
gravity!
Engine is in need of tuning.
Gravity. The car is heavy and doesnt want to move, so you must excelerate to make the car go uphill. If a car is going downhill, the is no need to excelerate because gravity is pulling the car downhill.
check the air intake
Time for a tune up.
Gravity if going uphill. Friction.
check your cruise control and make sure it is off, my car doe's this when i stop if the cruise control is on.
If the slope is 'uphill' then the car is going faster
Absolutely.