My car is throwing a check engine code 55 for ks signal circuit. Im kinda stumped as how to fix this. The motor ran fine b4 it was swapped into my car(2jzge). My car is also idling very rough till it almost dies and you have to literally floor it to catch its self. I bought my ecu from a member on here that says its a perfectly functional ecu. Is this a ecu problem or a knock sensor problem? any help would be greatly appreciated.

No one has any ideas? I know im not the only person who's ever had a knock sensor problem.