driving performance issues
 

I have a 2016 honda civic lx. ..bought it last year used... and when I accelerate at higher speeds faster like when getting on the fwy it just does not feel as smooth and quiet as it should. I feel like I'm driving a Hyundai. There is no vibration when I accelerate but I just seem to feel it more in the gas pedal and it sounds like the engine is working harder if that makes sense. I know nothing about cars but only thing I can think of is a possible exhaust leak somewhere. Honda looked at it and said it was the K&N air filter I had in but that was not it. It still feels the same when I drive it and I've driven other hondas before and this car really annoys me with this issue. Any thoughts or suggestions would be appreciated.