Engine Revs Up with no power?

I have a 95 madza m3 stick shift. It gets around on flat surfaces but when I go up a hill, the rpm's rev up real high and there's no power. It's like it's in nutreal in every gear.It happens 30 minutes after I drive it. The mechanic gave it a tune up but that didn't fix the problem. I took it back again and they lubricated something on the shaft? That didn't work either. Do you have any ideals, please help. Thank You, Sheryl