I own a 1995 Cadillac. Does it incorporate a module that adjusts ignition timing for octane?--At what interval?
It doesn't do it directly, but indirectly. It does, as Solar Mike suggests, have a knock sensor which detects knock (obviously) when it occurs. Knock can occur with lower octane fuels than what is called for or when there is carbon build up which causes hot spots in the cylinders/combustion chambers. When this happens, it can cause pre-ignition or knock. When that occurs, the ECU will pull timing (up to a point) to try and reduce or eliminate the knock. Like I said, yes it does have a module to do this, but only indirectly.