More than likely it is a fuel related problem. It could be a clogged fuel filter, the float level in the carb set too low, or the fuel pump may be going out. These are the first things I'd check.
The engine cooling fan clutch may be locked up.
Could be a loose or worn belt, or an accessory (water pump, alternator, etc.) bearing going out. Could even be a wheel bearing going out. Start by checking the condition/tension of the drive belt(s),
low transmission fluid or your tranny could be going out.
heater core going bad.
your clutch may be going bad
You could say the answer to be a notified answer but to be truthful when answering this answer you can say neither. Maybe could be acceptable but it is almost an impossible question!!!!!
It could just be the heat shield on the under side of the catalytic converter.
When it takes a car a long time to accelerate, the car may need a tune-up. Also, the fuel injectors may need to be cleaned or replaced, or the fuel pump could be going bad, or the fuel pressure is too low.
The window goes down easier because gravity is helping. The window tracks could be dirty or the motor could be weak, causing the trouble going up.
transmission is going out and bad
going up a very steep bend i stalled
sounds to me you might be having transmission problems. If you never got the transmission pan replaced it may be time for it. Its a gasket that goes bad and makes the fluid leak. I'd suggest going to aamco.