Same procedure. It'* the elbow you're after.
Do NOT run like that long-term. I suspect your PCM is pulling boost to protect itself for some reason.
I'd like you to compare resistance between both of your ECT'* for starters. After that, warm the car up until the problem starts, keep it running, and spray carb cleaner lightly on all vacuum connections, and around the base of the supercharger. If the idle changes, you have a boost/vacuum leak.