1992 Toyota Pickup No power, Idles fine

I have no power at all to accelerate, it jerks and nearly stalls out even when starting to move at all, can only get truck to move about 15 mph if it will even move, engine idles fine. Has a slight miss. Things that I have done to correct this so far, and have failed are: Checked and adjusted TPS sensor, replaced defective airflow meter, replaced tempature sensor, replaced EGR valve, replaced intake manifold and all seals on both parts of intake, fuel pump replaced, new plugs and wires cap rotor and coil, cheked pick-up coil air gap and resistance, checked and traced all vaccume line for leaks, adjusted timing to 5 degrees BTDC and also adjusted valves. Could this be the ignighter, O2 sensor, fuel pressure regulator or ECU. Or could it be something else like the TPS sensor that has cheked out fine with a voltimeter and adjusted within the range of operation.