[btwilson86]

The code 52 (knock sensor) is usually triggered by deteriorating wiring from the 2 knock sensors to the ECU. When this code is stored in the computer, it over enriches the air/fuel mixture (makes it very rich in fuel) and drastically pulls ignition timing, especially as boost increases. In my experiences in a Supra with a code 52, it will idle and drive fine at light throttle, but the car will fall on its face around 3000 RPM and have absolutely no power while under boost.

There are several good write-ups on the various supra websites on how to rewire the knock sensors using the existing plugs (there are 2 sensors under the intake manifold, you need to rewire both). Be sure to use shielded wire, as the electrical signal the ecu reads from these sensors is extremely fine, and any electrical interference from other wiring can cause problems and signal degradation.