Not really enough info in your question to give a detailed answer. If it doesn't accelerate at all it could be a transmission problem or even a simple linkage problen. If it accerates slowly it is possible you have a clogged fuel or air filter or clogged injectors. If it accelerates poorly at around 50mph or has a sort of rotten egg smell you have a bad catalytic convertor. There is also the possibility of a weak fuel pump. Sorry, that is about the best I can offer.
You may have a power steering problem.
You just press gas pedal :))
if it has a carburetor it is normal
press the break and call the car company you bought it from.
you have a worn rubber bush on the car. and when your decellerate it makes contact with the part of the bush that is worn and vibrates. and when you accellerate it lifts it away from the worn part. and the sound goes. so renew ALL of the bushes.
the motor is prolly flooding you might have a stuck valve
Idling too high?
You Should Take It To A Garage
Need to flush your fuel injector
A driver presses the gas!
Your ignition timing is WAY off.
You probably need an alignment .