Merzman

Had mechanic replace wiring harness due to oil fouling from the faulty left bank oil sensor (sits atop actuator pump housing). Car back and left bank would not fire when ECU senses load and closes left bank actuator. Mechanic thought it might be left coil pack. No problem with that before. Took to another shop. They dx'd the same, added in a couple of bad O2 sensors. Problem persists. Engine idles fine, but when load comes on and system calls for left bank power, the electronics will not send the spark signal to the coils. Any ideas? Anyone know how the system works? The mechanics are clueless and I've spent $5 k on this to date.