PA-46 pilot reported the engine began to run rough during takeoff roll at rotation speed; but elected to continue the takeoff due to the engine starting to develop power. During climbout; the engine continued to run rough and the pilot elected to return to the departure airport. The reporter stated the issue was a residual vapor lock from the engine start.

Narrative

Previous flight was a 4-hour cross country. Refueled and started engine after approximately 1-hour on the ground. Rough engine start; yet successful. Completed the standard engine run-up prior to takeoff without issue. On takeoff roll; just at rotation speed; engine developed a rough sputter. Rotated because the aircraft was developing power and determined it was safer taking the aircraft into the air. On upwind the engine continued to run roughly. I turned crosswind and downwind and informed the Tower I wanted to return for a landing. The Tower asked if I was [requesting priority handling]; to which I responded in the affirmative out of an abundance of caution. After an uneventful landing and clearing of the runway I terminated the [priority handling]. I was directed to an engine run-up area where I preformed multiple full-power runs to clear and assess the engine. Once I was satisfied that the previous malfunction was a residual vapor lock from the earlier difficult engine start; I informed the Ground Controller that I was prepared to take off. Subsequent takeoff; climb; and flight were uneventful. Support from Tower; Ground; and operations personnel were exceptional.