Compressor starts and stops at end of running cycle.

This air compressor is used to keep a stead pressure on a system...the air is not "used" up on a daily basis as in an auto-body shop or garage. The air compressor was running quietly and for "normal" run times. Over the last six months, it has gotten noisy and runs more often. The biggest problem is that at the end on a "run" cycle; the air compressor stops and starts several times in a few "seconds".