89 Accord LXi sluggish below 3500 RPM...

When accelerating, the car is sluggish until about 3500 RPM, then gets a boost of energy...feels like a 4 bbl carb when the 2nd 2 bbls open. Above 3500 runs fine. I've changed out cap, rotor, wires, plugs and fuel filter (ARE THERE 2 FUEL FILTERS?) and still have this minor problem. Any help is really appreciated. Its a 5 speed 4 door with about 140K miles.

Have you checked for exhaust leaks or cleaned your fuel injectors? Don't forget to change your air filter as well.

Air filter is changed regularly and didnt help this problem. Can I clean the injectors myself?

Well in a car with smaller amounts of displacement, the torque sort of "winds up" through the rpm range. It sounds like that's what your car is doing. I'm guessing full torque is reached at 3500 rpm? In a larger displacement engine, for instance a Trans Am with a 5.7L V8, there is a large amount of low-end torque.

There might be something causing the sluggish low rpms. I would say the fuel injectors need to be cleaned or the exhaust as Plastic_Fork said. You can buy STP Fuel injector cleaner which runs through a tank of gas. Not sure how well it works, but it's an option.

Good luck.