Hello, I'd like to pick your brains for possible fixes. I have an 87 Blazer, EFI, 350, and 350 Trans. The engine runs smooth and strong except for when I am at a stop with it in gear. It will then slowly start to drop RPM's until it finally croaks. This is with the engine fully warmed up. Does it sound like a vacuum problem or somthing else? If so, what is the best way you've found to locate the leak?