I have a 99 cav and the check engine and ets off light went on this morning. What does this mean and what do I need to do to fix it?

We need to know what code was set in order to have a chance to help you out.

Check for the exact codes, by attaching a code reader. Problem is likely ignition system related. Ensure the platinum spark plugs (ACDelco only) have been changed in the last 50,000 miles. Go over the entire ignition system, paying particular attention to the Ignition Control Module and coil packs. The ETS will be turned off, if there's a problem with the ignition system.