Hi, I've got an ongoing issue with my 93 WRX import with flatspots/hesitation in the power delivery. I've changed the MAF from a working car and tried a working knock sensor of another car but after an ECU reset I am still getting code 22 through the check engine light and still have the hesitation.

I have took a reading of 5 volts from the connector the knock sensor plugs into on mine but on a working Impreza (94 wagon import) and that only shows 3 volts on the same connector.

Is my higher voltage causing the circuit to indicate an error and the ECU to change the fueling - hence the loss of power and flatspots etc? What is the voltage the Knock sensor circuit should be running at? Could a short in the wiring cause the high voltage?

Or am I looking in the wrong place and the engine is just knackered?