BREADFAN

I have a 98 civic dx 1.6, it gives p1300,p1301,p1302,p1303,p1304,and p1399 codes. It misses under load only. I replaced the fuel pump, regulator, and filter. I swapped the injectors from my daughters car (same make,model,year). Replaced the distributor, wires, plugs, and distributor again. Main relay, ALL engine sensors, ALL fuse inside and out, ALL relays inside and out. Even though it passed all the compression tests and leak down test, I put a new head and head gasket on it. I got an ECM, and it had an ignition switch recall I had done. I have ohmed all the wiring to the ECM and fuel pump. I'm so lost as to whats wrong with this car. It was perfect a month ago, getting close to 40 mpg, now it runs like crap and gets about 20 mpg. I do not care about the mpg I just need this thing to run right. If anyone could point me in a direction to fix this thing I would be so happy.