start by pulling the 15A EFI fuse in the engine bay fuse box, near the battery. leave it out for a minute. put it back in, drive the car, and see if the code comes back. if so, read on:
code 52 has nothing do with anything besides the knock sensors. either A) one or both sensors are bad, or B) the wiring is shorting out somewhere.
do this first:
http://www.supras.com/06/techcenter/display.php?QID=69
and if that doesn't work, then replace ONE knock sensor. if you still get the code, then switch the good KS to the other location, and put the other old one in the location where the new one was, still have the code? get another new KS. still have the code? you screwed up the rewire.
just because the KS harness looks good doesn't mean that it is. that's like looking at a can of applesauce and saying: "well, the can looks good, so i'm sure there's no mouse poop in it."
chances are: switching back to the old AFM and 440's won't fix your problem. turbo shaft play will decrease overall power output, but will not cause the code 52.
ECU's RARELY go bad.
-shaeff
