I would suggest you check a few simple things before throwing parts at it.
1) Accelerator cable: Is it adjusted properly.
2) How's you air filter? Any obstructions in the air intake system?3) Fuel flow/pressure . On spec? Kinked fuel line?
4) Check ignition timing.... and camshaft timing.
5) Catalytic converter clogged?
6) Coil output?
JackD