2007 f150 p2004 code

I just replaced the motor in 2007 f150 5.4l {crate motor} truck runs great but I have a p2004 code for bank 1, imrc stuck open took off intake ckecked for pinched wires or bound linkage but both butterflies seem to work fine so my question is how can I have a code for only 1 side and what senses this code, thanks in advance