3.1 Engine hesitates after restart when hot

[Meridivs]

Recently our '92 TS has developed a strange problem - it pulls and runs fine but once we stop the engine when hot and restart it it doesn't run right and hesitates (power comes and goes in waves, regardless of acceleration).

If we keep the engine on, cooling fan cycling, it runs fine with no issues but once stopped it hesitates after restarting hot.

Have you experienced this? What might be the case for such strange behaviour?