i have a 94 z28 and was wondering if this sounds like a cracked manifold. When i start the car you can hear the exhaust leak but it also make some kind of squealing(whistling) noise. After I drive the car for awile you dont hear the leak or the squealing noise. As soon as you turn it off and let it sit for a couple of minutes its back to the leak and noise. I hope thats all thats wrong. I just bought the car and think the trans is going out. Also just wondering if the exhaust leak will hurt the performance of the car too.

Thanks
Josh

 

When you first start the car, try to locate the sound. There is generally some black soot visible at the point of a leak. Any leak will affect the O2 sensor readings and therefore alter fuel delivery.