Ok so I have a '85 4runner with a 22re. I changed the oil Saturday afternoon and all was good. Drove to work Sunday morning and went wheelin Sunday afternoon/evening. Today the oil pressure dropped and there isn't much oil in it. It's not leaking and it's not burning oil. I have no clue what's going on

 

Are you sure you put enough in to begin with? Oil doesnt dissapear without getting burned or leaking out. Have you climbed under and looked for leaks? Just because there is no oil spot in the driveway doesnt mean it isnt leaking, also check for damage to the pan from wheeling maybe.

 

maybe the old gasket from the old oil filter stayed stuck to the block. the filter wont seel right and it will leak when you have oil preasure. ie: when the truck is running.