Taylor, it depends on your definition of "kouki". Could be J4, could be E5.

In the mean time... If the engine is running on all cylinders (idle considered reasonable under ANY condition), then your ECU matches your harness. J4 and E5/62 have a few pins connected differently at the blue plug. The most noticable are that ignition for cylinders 1 and 2 are moved. Trying to run an early blacktop with a J4 will have your car imitating a Subaru or dying lawnmower.

It could be just the MAFS. As soon as the ECU doesn't see the MAFS, it goes into limp mode. Instantly. It's like flipping a switch labled "old jalopy mode". Just to let you know, as long as the car starts and fires on all cylinders, the ECU is fine.

Again, check the codes. It doesn't get any simpler.
"hey car, what's wrong with you". <turns screwdriver>
"bliiiink, blink blink".
"oh, maybe I should fix that".