Why does your 1985 corvette idle a little hi when its first started then idles down low and you can hear the cam after about 10 seconds again?

The 1985 Corvette is equipped with a Cross-Fire Injection (CFI) system, which is a type of fuel injection system. The CFI system uses a computer to control the amount of fuel that is injected into the engine. When the engine is first started, the computer sets the idle speed to a higher level in order to warm up the engine. As the engine warms up, the computer gradually reduces the idle speed.

The camshaft is a component of the engine that controls the opening and closing of the valves. When the engine is idling, the camshaft is rotating at a low speed. As the engine speed increases, the camshaft rotates at a higher speed. This change in speed can cause the camshaft to make a different noise.

It is normal for the idle speed of a 1985 Corvette to be a little high when it is first started and then idle down low after about 10 seconds. If you are concerned about the noise that the camshaft is making, you should have the car inspected by a qualified mechanic.