At the risk of sounding like a stuck record. The same thing was happening to me. It was my oil cooler being toasted. You can pull it out and visually inspect it, or you can see if there's oil in your coolant, you can also see if there's oil/coolant leaking above your oil filter.
It could also be your IDM or your ICP sensor. Have you had a mechanic buzz test or contribution test your cylinders/injectors?