I hav the exact same problem. It was cooler in the morning, then it got kinda hot durring the day, and it started to slip, and i had to accelerate real slow, but then when it got cooler it was fine. And it only happened one day.

I was leaking power steering fluid and thuoght maybe some of it got on the clutch and made it slip?

I just had a 5speed conversion done last week, with new master slave and drive shaft, the clutch was slightly used, so im not sure what it could be, if someone can help, it would certinaly be appreciated.

 

Adjust your clutch pedal. That's the main problem, I did that and it solved my problem.