Did you perform a power balance test? Isolate the cylinder(s) then inspect the wiring to/from. If it appears the plenum has been removed in the past to service/change the injectors, you might have severely pinched O-rings, so you're just dumping fuel into the cylinders. IDK if this causes code 45, but most of the times we see bad/dead injectors and DON'T have any CEL/codes. Happy Z-ing!