Toyota Repair: Code 52 Toyota 4runner, blown head gasket, toyota 4runner

Question
I have a 1991 Toyota 4runner 3.0 v6 engine. i purchased this vehicle with blown head gasket.  So I reconditioned the heads with new gaskets, injectors, plugs , vacuum hoses, the works.  Engine runs and idles great.  However when i snapped the throttle the check engine light comes on and I get a code 52 which is the knock sensor.  So I pulled everything apart changed knock sensor and it's connecting wire that runs below the intake.  I still get the code 52.  What else could it be?  ECU?  Anything would help.

Answer
I've never encountered a failed Toyota ECU, minus the "Prius" problem. The ECU should be fine. The knock sensor codes are triggered only by resistance on the line. If the ECU see's ground/very low resistance, the code trips. I'm betting the wiring, or the new sensor is bad.

Those ECU's sell for around $25 used. You can always try putting in a new ECU, but I would be extremely surprized for that to fix he problem.