This is not on a Supra, but I figure this would be a good place to find an answer. I have a '94 Chaser 1JZ-GTE automatic. The car drives completely fine under normal driving not on boost. When I try to take off and get into boost I can hear the leak especially next to a concrete wall/sound barrier. It also won't pull all the way to redline, it slowly gets up to 5K RPM then shifts. If I'm already rolling and try to get into it the revs raise but the car doesn't downshift right away, then it drops a gear and same problem as trying to boost from a stop. I've leak tested the inter cooler and piping, didn't find any there. The TRC light has been on since I bought the car, unsure if its related.