1992 corvette runs and idles very rough I get a code 72 VSS Does that have anything to do with the running or what might it be?

Code 72 is indeed related to the Vehicle Speed Sensor (VSS), which is responsible for providing information about the vehicle's speed to the Engine Control Module (ECM). A faulty VSS can affect the engine's performance, including causing it to run rough or idle poorly.

Here's how the VSS malfunction might impact the engine's operation:

1. Inaccurate Speed Signal: A faulty VSS can provide inaccurate speed readings to the ECM. This can confuse the ECM and affect its ability to properly manage fuel injection, ignition timing, and other engine parameters, resulting in rough running and idling.

2. Transmission Shifting Issues: The VSS also plays a role in the automatic transmission's shifting strategy. If the ECM doesn't receive accurate speed information, it may not shift gears smoothly or at the appropriate times, which can contribute to the engine running rough.

3. Fuel Delivery Problems: The VSS input is used by the ECM to calculate fuel delivery. With an incorrect speed signal, the ECM may not be able to accurately determine the amount of fuel needed, leading to either a rich or lean fuel mixture and affecting engine performance.

4. Engine Timing Problems: The VSS signal helps the ECM determine the correct timing for spark plug ignition. A faulty VSS can disrupt the proper timing of spark delivery, leading to engine misfires and rough running.

While the VSS malfunction can contribute to rough running and idling, it's important to note that other issues could also be at play. To accurately diagnose the cause, it's recommended to have the vehicle diagnosed by a qualified technician. They can use diagnostic tools to further analyze the issue and identify the root cause of the rough running condition.