If the tracked counter was part of a multi-unit formation and you'd paid 1SP to fuel the entire formation, it would remain fueled until the next friendly cleanup phase. So you'd pay for fuel in the movement phase for the partial move in reserve mode and it would still be fueled in the exploitation phase and eligible to move its fuel MP upon leaving reserve mode. The formation would lose its fueled status in the cleanup phase.
If the tracked counter was an "independent unit" you could use the HQ method. Pay 1SP to fuel an HQ; it remains fueled until next friendly cleanup phase and can provide fuel to any independent unit within throw range (check 12.5e for the limitations). So pay to fuel the HQ in the movement phase and it could throw fuel to the tracked unit in both the movement and exploitation phases (subject to the limitations in 12.5e)
If you paid 1T to just fuel that one tracked counter, it would remain fueled only for the current phase; you'd need to use another 1T to move in a later phase