1993 Ford Festiva intermitten

The car sometimes runs fine and other times it cuts out and loses power. Sitting still idling it does not appear to have a problem then at times it starts fluttering and acting up when I drive it and floor it, it stops running when I back off the throttle it runs again it's really bad when I put a load on the engine, here is what I have done also sometimes when I start it at times I have to pump it a couple of times but most of the time idling its very smooth

Rotor cap and wires plugs
removed gas tank and cleaned fuel pump pumping good
changed coil
checked wire ends looked for air leak none
getting good spark
check to see if it jumped a tooth on the timing it did not
checked timing good
replaced catalytic converter
cleared out fuel lines and injector rack
replaced o rings on injectors
cleaned engine plug connectors


when this car runs at top end 40 to 50 mph it jerks and surges real bad and misses and sometimes idling I can hear the injectors picking up and slowing a minor surge you might say is this the computer? Does the injectors run on a inline fuse? What it acts like is the timing and injectors are not progressing with the R.P. Ms could the computer codes be out of sinc?