My 87 5kqt has an interesting problem. When the car hasnt been running too long (even if I drive a half hour, get out for 5 minutes then start again) I have what sounds like an exhaust leak when I am in high rpms in the first three gears (when turbo is working the hardest?). The noise will suddenly cut out in 3rd gear when I shift into fourth and then it is non existent. When I am in neutral I can rev the car and the exhaust sounds fine. Also if I have been driving for a while the noise becomes much less prevalant or non existent. I do not know too much about cars and I definitely do not know much about turbos! Could this possibly be a symptom of a turbo problem? Any help is appreciated!