Poor acceleration my car in a very good state but sometimes it has very poor acceleration.

Replace the air and fuel filter and have the catalytic converter looked at. It's common for the catalytic converter to go bad and start to restrict the exhaust flow. This is more noticeable when the exhaust system heats up rather then when it's cold, once the cat's heats up. The screen in the housing plugs up causing the restriction, you can go to any muffler shop and have them check the catalytic converter and most places do this free of charge. Good luck