I have been having problems with my car for some time with acceleration. It starts just fine, but every now and then there is some hesitation in the idle. When I am accelerating up a hill it revs up and down even though my foot does not move on the gas peddle. I though it might be a problem with a fuel filter but I am not sure where that would be located. I have been trying to search the internet for solutions, especially since I replaced the O2 sensor hoping it would fix the problem, but it still runs really rough. I want to avoid taking it to the dealership or a mechanic and end up spending to much money. Any thoughts or ideas as to what this might be related to or where I can start from here? Thanks!