Won't idle, acting strange

[SHEARER_TSI]

I've been rebuilding this front drive turbo and I finally got it to fire up the other day but its acting really weird. It is really hard to get to start, like i gotta give it mad throttle and crank the shit out of it to get it to run. Once its fired up it wont stay at a consistant rpm, and it dies out completely it you get off of the gas. Its almost completely stock with the exception of a walbro pump because the stock one was dead. Its got a brand new fuel filter, plugs, and wires on it too. The head gasket is brand new and so are the head bolts, i dont trust re-using old ones. The timing is set as close as I can get it with it running weird and I checked all over for vacuum leaks too. It has no check engine light on and everything seems to be in good working order. I messed with the idle settings and completely flushed out the old fuel and put fresh in it. I seafoamed the motor to get the crud out of it too. From what I was told the ecu was rebuilt shortly before I bought it so I dont think thats the problem. The entire throttle body came off of a running car so it should be good too. Could a gunked up fuel injector or bad pressure regulator be doing this? Its got good strong spark so im thinking its a fuel issue. Anyone have any ideas as to what is up with this damn thing??