The ignition distributor's functionality is crucial to the performance of your engine. Consider how critical it is for the spark to ignite the air/fuel mixture precisely when you time it to across its whole RPM range. If this ignition is off by just a millisecond, performance might not be optimized or worse, detonation may occur. Over time, distributors wear out their internal bushings and the centrifugally weighted springs lose their effectiveness. This can cause play in the distributor shaft and alter your timing curve. Rebuilding the distributor is an option, but parts are not easy to obtain and special tools may be required. At the first signs of trouble you should replace your distributor with a new or professionally rebuilt unit. This is much more favorable than being stranded on the side of the road and dealing with major engine damage.