ok im getting a code 3 at idle and i dont know y , the safc says the voltage from the map is 2.8, my multimeter says its 3.6 regardless i put it to -40 high and low throttle no luck, if i put on a missing link the cel goes away immediately. att this is at idle, any suggestins , am i supposed to read 5 volts at the ecu for the map or not, thanks