I just got a 96 camry and had the clutch replaced, and I'm getting the similar shutter, more so in first gear, but other gears have some too. In my case, if I put my hand on the shifter, I can feel it bunces up and down (mostly in first). I think it's the engine mount going out, too much drive train movement. Do you feel that on your pedal only? or through out the whole car? and No, it's not slipping. Go 2K rpm in 4th gear, push your gas all the way in, if you don't see the tachometer shoot up without increase in speed, your clutch is not slipping.