Rhythmic Morning Tic

The morning tic. 05 jeep liberty 3.7. 188,000 miles. At a cold start. With an obd2 reader hooked upped. The engine sounds smooth. But once it gets out of its cold closed loop. ( when the,short term fuel trim picks up) I get a tic. But it is rhythmic in nature. Starts off soft and then it builds in sound. Then it just stops. Then 5 to 10 seconds later it repeats. tic tic tic Tic Tic TIC TIC TIC TIC TIC stops then it repeats. If I idle up I can still hear the tic pattern. But it is much faster and duration is also shorter. Tttttttt............tttttttt......ttttttt..... As it warms up the tic gets shorter in duration and the no tic get longer. Once temp gets around 150 the tic stops. It's the same tic pattern every cold start. Changed spark plugs 8,000 mile ago with iridium.Why is it doing this?