easy way to check for air leak in intake ..get a can of carb cleaner carfully spray around intake manafold ,injectors,TB,and any vac lines ...as you spray the intake with engine running listen for rpm Increase and drop when you hear that you found your leak ..then repair ...also make sure you have good exaust flow at tail pipe ..if your exaust is cloged (at the cat or other area ) it will be very hot with little to no flow , if you still have a cat in the car i wouldnt drive it with the egt gauge that high you could make enough heat to melt the cat and start i fire ,iv seen two older supra's do that .