ignition problem need some help??

[boostcreep5150]

Okay guys when I start my car it will run for like five seconds and then it shuts off like there is no power to the coils hit the gas and nothing . I changed the ignition switch unplugged turbo timer,bypassed safc and looked for loose wires.It seems to be the computer.it doesn't do it all the time, but when it does do it if I start it and put it in gear and roll forward or backwards a few feet it will stay running car runs great other wise. It doesn't shut off while I am driving or anything I think it may be the ECU any feed back would be appreciated.

mods are;
rb25 s2
freddy mani
afpr
t3t4
stock injectors
safc2
full exhaust