2003 Honda Accord Weak Performance

I have a 2003 automatic Honda Accord it has 93,052 miles on it. In the last 8 months I have had the breaks done, all ther fluids changed, regular oil changes, all the filters changed, and I got a new battery 6 months ago. When I took my car to the dealership to get a new battery they told me they checked everything out and I should not have to get anyhting else replace until I hit 100,000 miles. Now when I try to accelerate past 20 miles an hour the car is slow to accelerate. And it is taking about 30 secs to start when I try to turn it on. But if I don't drive it for a day or so it starts quicker and runs better. It feels like it is not getting enough power to run properly. The more I have to stop and go the more problems I have. So it acts up the worst if I have to drive it in town and stop at traffic lights alot. I am taking it to the dealership soon, but I want to know what do you guys think is going on?