This problem could be caused by any one of a number of things. The fuel pressure is a bit low (pump maybe) but I don’t think the problem is due to the pump.
Possibilities could be, other than those mentioned:
Vacuum leak.
Idle Air Valve. (Not a rare problem.)
EGR stuck open.
EGR plate gasket rotted out. (On throttle body. Coolant can even leak into intake.)
Ignition timing way retarded. (Easy to do if ignition module has ever been dinked with as this engine is a TFI model and the SPOUT connector was not considered.)