Engine knock problem

I own a 1990 gt, bought it a several months ago and basically since then its had a loud knock from the engine. I'm not exactly sure where it's coming from within the engine, but I'm trying to narrow down the possibilities of where to start looking and how much it might cost to fix with some friends.

(putting oil in softens the knock very slightly, but with a bad oil leak the noise comes back within seconds so I'm not sure if it has any connection to the knock).

It is a constant knock and gets louder and faster as I accelerate. There doesn't seem to be any major loss of power, acceleration and speed feel the same as before. I'm guessing it could be a rod or valve, but what's the best way to find out?
Any other advice might help so toss anything out there.
Thanks!!!!

the oil leak is your first concern! without oil the pistons are metal to metal, NOT good.

yeah, i agree...as soon as it stops raining up here im going to clean the engine and locate the leak, then itll be time to look into the knocking.

swounds like ur engine is fixing to bite the dust. how many miles on it?

tkae a stethecope (thing dictors use) and find out if its from the block or head, block means rod, head means valve, or retainer

when i was younger and first got my celica i ignored the knock and being young and stupid, not to mention unknowledgable about cars, drove the piss out of it. then one day, chug-a-lug, my car cant accelerate above 25mph and rod is blown. hello new engine replacement, goodbye $900

It has around 150,000 miles.
yea I definitely want to avoid making anything worse, ill tackle the oil leak this weekend and hope to look into the knocking asap. think the haynes manual would help with the repair of it or are there any good websites that go through the steps?

better fix the pistol, i think it's the piston... or wait for the engine to crash and then buy a new engine!!1