Car is an 87 Firebird 5.7 TPI auto, engine built 3 yrs ago with new sensors, O2,IAC, IAT, MAP, coolant temp, ignition mod/ coil...No vacuum leaks, grounds are good, good spark plugs and wires, reman injectors 24lb all in range of 12.9 -13.5 ohms.
Been having issues for some time now, flash the EBL with an almost stock settings for 5.7 auto (change injector flow), car runs great in open loop after about 10 min in closeloop learn it decides to surge, hunting up and down the rpms lean to rich.
It fools me into thinking that I can go for a VE learn but it just starts surging out of nowhere.
If I disconnect the batt for a few min and try again it runs the same like I decribed but I try to crank it again right after the surging it continues with the surging even worse until it wont start.
Im stuck with this problem and dont know what else to try, any help would be appreciated.

 

I know you said you didn't have any vacuum leaks but it sure sounds like you've got one. Have you checked your vacuum pressure?

 

Steady at 18.