I have been fighting this code for over a year and it keeps returning. I have replaced the knock sensors with ACDelco, replaced, the harness, made sure I got resistance at the sensors and a base. 0.5 voltage at the connector, replaced the ECM, Idle air control, Egr Valve, and rewired the front 02 sensors. Im stuck, could it be the engine itself causing this P0327? I'm a mechanic but this one has me stumped
With those miles, yes as carbon buildup in the head can increase compression and cause the knock. With what you have done, I'd think this the most likely cause of the knock. When ya get on it a bit, can ya hear it knock? Also, increase octane significantly to see if the code quits being thrown (high octane allows more compression/timing without knock).
Is that the only code returned on the scan? You may have 2 knock sensors?
It only knocks on startup and smooths out. That is the only code on the scan and all of the live data looks normal for this engine at those miles