Is there any smoke when you step on it and notice the loss of power? Also i threw a turbo pressure code (turbo overboosting). Not sure if that does anything to the car as far as the ecu trying to let it drive without harming anything.
When it happened to me, i was at the track. 1st pass went smooth,2nd pass was when i noticed the power loss. I let the car sit for almost a hour trying to see what the problem was. took it out for a third pass and it ran fine again,then 4th back to shit. Got it back to the shop and put it on a rack,discovered the cracked hose,bought on from toyota($115 wasted ,due to the fact i bought cooleeze 2 weeks latter) and never had that problem again. so it can happen!