AC suddenly stops then next start, its working

AC was running fine, then next startup, its not working (blowing normal but hot) .....after restarting engine, the AC is working again. Could this be a sensor or something else going out?

Next time it is not working when it should- take a look at the front of the compressor. Is it turning? most likely not.....very common issue is a wide air gap....where the electromagnetic coil can't pull in the clutch when the coil is warm. Cold start up is fine, resistance is lower when cold, but soon rises enough that after the first cycle, it can't overcome the wide air gap. Answer is to pull the front of compressor clutch driver off and remove a shim and re-install - the air gap will be less and you can go another 100k miles until the gap wears too wide again....