check to see of your firing order is set proper.. if you get your sparkpug wires wrong it can cause your car to do that too.. or if all your injectors are firing... while the car is at idle use a long screw driver and place the tip on any part of the injector and place your ear at the handle end of the scree driver .. listen to hear ofr a sharp ticking.. if you hear it then yoru injectors are working.. if not check your connection... id start with that first... if everything is working right then id check for a vacuume leak..

 

Sometimes those injectors go bad too. They may work ok, but aren't putting out quite enough fuel. Or it could be a mixture problem like a bad throttle position switch or AFM.

Possibly a vaccume leak too. Maybe your timing chain is stretched and causing you to lose torque. This along with other mixture problems could very well cause your car to have no power under a load.

 

In my experience with most cars....a stutter under load that disappears under no load is most likely an ignition miss. Pull your plugs and check for burn patterns on the porcelain part of the plugs. Sounds like a bad plug or wire to me. Were you chasing a miss before and thats why you replaced the distributor and injectors?
Hopefully this helps you out.
Gary