PA-28 pilot reported safely diverting to an alternate airport after experiencing a power loss.

Narrative

Just passing ZZZ airport I encountered significant power loss in the engine. Flight was normal up until the 53 minute mark of the flight and then suddenly and without any action on my part the engine lost power. I performed some limited trouble shooting in the air but being over a highly populated area I did not want to take further risks. The engine did not appear to cut out or sputter but simply started producing much less power. It came back briefly to normal power but then again dropped back to reduced power a second time which was not sufficient for sustained lift.This description was further backed up by the data from the G3 engine monitor showing almost 0 fuel flow over several minutes after the first power loss.After the second power loss I made the decision to continue a return to ZZZ as part of the initial [request for assistance] and was cleared for landing. This was the safest and most prudent action to ensure the problem did not escalate out of the safe distance of an airport. The landing was uneventful and I taxied to the FBO.