LS computer gurus. no power at fuel pump

[chevydog66]

Ok, so my truck was running fine for over a week. It has had reoccuring codes 0134 and 0154 o2 sensors no activity. I have cleared them and they keep coming back. I installed 2 new Bosch o2 sensors when I installed the motor. I am running DT 324 headers. I hooked up efi live and it shows the o2 sensors are heating up but also shows a flat line which should be an up and down line. I checked voltages at the harness that plugs into o2 sensors and get 11.3 to 11.8v. So today I get in it to go to work it starts and runs for about 3 seconds and then dies. Wont start back up. I checked fuses, good. I check for power at fuel pump, no power. I check for power at fuel pump relay, no power. Any ideas? Is there a failsafe built into the computer that would shut down pump? I also checked red and blue connections at the computer. Removed + and - battery cable for a minute or 2. What the?