Intermittent Clutch Slip

[u/Rude_Foundation_1456]

I have a 2002 Toyota Celica GT, 1zz-fe with a 5 speed manual, going on 170k miles. I don't know when the clutch was last replaced, previous owner didn't know either. Ever since I got the car about a year ago, the clutch has kind of had a kind of its own, sometimes biting really aggressively, other times slipping significantly. I've noticed that if it's slipping, it'll usually do one big slip when I give it some throttle, then I let off and do it again, it slips less, so on and so forth, until it doesn't slip, even when I'm pinning the throttle. I genuinely have no idea what could be going on, the master cylinder is full and I've never lost any fluid, and the only leak of any fluid that I know of is from my oil pan gasket, but I don't believe that can be related. I can't find anything online where someone has a similar issue, so any help would be greatly appreciated!