delayed acceleration could e due a number of things assuming there is no check engine lights or engine missing issues. It could be due to deferred maintenance ie. dirty air filter or old spark plugs.
It could also be due to choked catalytic converter generating back pressure for the engine.
A high mileage car with bad maintenance i.e. delayed oil changes may also have a weak engine hence reduced pickup.
there could be an issue with the clutch as well. i.e. if its not disengaging completely. could be due to worn out clutch plates or the clutch needs setting (if the clutch disengages very late)
