Not the alternator I’ve checked the alternator and wiring from starter to the fuse box and I’m not dropping voltage on any of these including the battery, it only happens to the ecu under load so I’ve contacted wiring specialties to see where the ecu is getting power cause I’m getting a voltage drop on that wire which I just found today but none of my connectors are labeled power. I did run a separate wire to double check and sure enough I was stable at about 13.5v even under load