Oil pressure is unstable. What could cause that?

Are you asking me what I mean, or what engine, or ? 2000 Chevy S-10 PU 2.2 Gas powered 4 cyl. five speed manual. Oil gauge goes up and down. Just had it changed and topped off a week later. Uses alot of oil but never see smoke and never see any leaks.

Actual oil pressure can be tested with manual test gauge.. The 4.3 L V/6 engines give more oil sending unit problems than this engine... ALWAYS include engine size and model when inquiring about a vehicle!

alright. Thanks. So are you saying that it is probably the oil sending unit?