All grounds should be at the common G101 point on the intake manual. Clean all the eyelets of the wires you found there, and the face where the wires contact the intake manual, then reinstall. Don't ground sensors from various points. The ECU expects the ground reference point at G101. Be sure G101 is grounded well to the mounts, the mounts to the body, and the body to the negative terminal of the 12v battery. Note that some sensors may be powered by the ECU at +5v, so their grounding is critical. Also, unplug the engine wiring harness from the body and replug it a couple of times to clean it. Same with the 3 plugs to the ECU if still having a problem.Could there be some problems with the internal electronics? Go to the repair shop and check it.