PA28 pilot reported during takeoff they experienced a rough running engine resulting in a rejected takeoff.

Narrative

Aircraft X completed its annual inspection and was returned to service by my A&P IA (Inspection Authority). I performed a full preflight and run-up in accordance with my checklist and found everything operating normally. I then departed runway XX at ZZZ for a post-maintenance test flight. Shortly after rotation; I noted a slight engine roughness. I had ample runway remaining and determined the safest course of action was to reject the takeoff and land straight ahead. I taxied back to my hangar and contacted my mechanic.The mechanic inspected the engine; including fuel; intake; and ignition systems; and found no discrepancies. I conducted three high-speed taxi tests on runway XX; during which the issue did not reoccur. I performed a run-up before each test and noted everything operating normally. I subsequently determined the aircraft was in good condition for safe flight and conducted a box-pattern flight over the airport. The flight was uneventful; though I observed slightly elevated CHT (Cylinder Head Temperature) on all cylinders. I had both magnetos re-timed and synchronized. CHT levels returned to normal; and the aircraft has operated without issue since.