The ECU on this Pathfinder 1988 doesn’t have a switch to select the mode. It blinks both red and green lights once the two time then three times then four times and then repeats. Is the diagnotic ON/OFF used some way to select the mode. The Haynes book shows a rotory selection switch. This unit doesn’t have such.
The engine starts “loaping” after starting and idling smoothly for about a minuite. Pressing throttle results in cut out, stumbling and coughing to a stop.