2001 Jeep Grand Cherokee engine hesitates

2001 Jeep Grand Cherokee mileage: 118,000. My Jeep Grand Cherokee was running great until a few months ago. Now when I am accelerating slowing from a dead stop the engine hesitates until I get up to 30 to 35 mph. Then it begins to accelerate smoothly. I have changed the distributor cap and rotor, the spark plugs, had the injectors cleaned all with no help. The fuel filter was changed; it helped for a few minutes and then it started doing the same thing again. Is there anything else I can do before I take it in to a shop? The engine only hesitates and surges at low speeds but it seems to be getting worse. Now if you accelerate very hard you do not notice it, but if you are accelerating normally it is bad. Thank you for any help you can send my way.