After doing oil change myself, I found that the engine is very hard to exceed 5K rpm even I fully pressed the accelerator (at P, not N).

On road, I start from 0 mph then fully pressing the accelerator, it reaches 40mph after 6 second. However, the acceleration is much lower than before.

I guess the fuel pump needs change, also the fuel filter. I did not see any check engine light and other problem.

Is my feeling reasonable?

Another idea is that, if I just keep the current situation, I feel I can improve the fuel economy as it hardy let me over accelerate. Right?