need some LS help

[hubdawg]

Transplanted a strong running and driving 2004 tahoe 5.3 out of a 72 k10 into my 72 blazer and running into some problems with the transplant. I did a frame off resto on the 72 and installed a painless harness. When I try and start it it runs super rough at high idle and quits within 5 seconds.. I ran the same inline pump from the k10. If i run an OBD it only shows O and OH flashing with a solid yellow light. Any ideas on where to start