1989 Ford Festiva Idles fine bogs on acceleration

I purchased a 89 Ford Festiva L. The fuel pump, fuel filter, Dist. Cap, rotor ignition coil, plug wires and the exhaust from the manifold back have been replaced new. It starts, runs and idles fine, after a couple good cranks. However, when I press the accelerator down it bogs, spits, sputters and idles extremely rough with no power, until I release the accelerator, then it once again returns to a nice idle. In doing my own hit and miss research, I found out there is one check engine light code #81. I have since replaced the MAF sensor, O2 sensor. After installing the MAF I reconnected the MAF connector and start the car it idles for a second, then dies. If I unplug the MAF cable and start it runs as before, no change in accelerator issue. The MAF plug was not an issue prior to change. Following the manual I checked the power relay it was ok, however I found the fuel pump relay as faulty, I replaced it and still the same issue. I did however, find out the previous owner ran a switched 12v lead directly to the Grn/Y wire on the fuel pump connector, so the fuel pump runs continuously when the key is in the on position. The Grn/Y wire runs back to the fuel pump, I assume it gives it power. Eliminated the direct switched 12v lead the previous owner installed and I am running with the relay as intended, when I check voltage at the fuel pump plug I only get a cranking voltage of 8-9 volts. Pump does not turn on. Of course when I reconnect the switched 12v lead it works? I can operate the pump as the previous owner has rigged up. I am still perplexed about the bogging issue. Not sure if it is a fuel pressure issue I bought a gauge) or a timing issue. I am using the buy the component and see if it works process, It is getting expensive. I need help in narrowing this a little further and in the right direction. Any advice would help.