Since you did not say what the year, make, and model of the car is, nor how many miles it has been driven; it is much harder to answer this question than it would be if I had that information. There are many differences between brands and years of cars; so the answer would be different; depending on what car you have.
But without knowing any of that information; the best advice I can give you is to find out whether this car has a fuel filter. If it does; then have the fuel filter changed. The fuel filter is not the same as the air filter; so be sure it is the fuel filter which is being changed.
If this does not fix the problem; please write us again, by clicking the button below this answer, that says "answer this question" and tell us the year, make, and model of your car; along with the number of miles on it, whether it has a manual transmission (which would have a clutch pedal in the car) or an automatic transmission, and anything you know about the engine size and number of cylinders.