Let's have a quick look on oil pressure
If your engine is too hot, your oil pressure should drop (yes drop), if your engine is too cold your oil pressure should rise. So to influence your oil pressure you should manage the temp of the engine.
If the temperatures are normals a drop in the oil pressure mean probably a leak in the oil system (so probably a hit) or a lack of oil, but the sim hopefully don't simulate the need to replace oil before takeoff^^ or the oil pump is broken.
If the oil pressure rise (while temps are OK) then something is probably blocking a pipe in the system.
When the oil pressure is too low your engine is not correctly lubed (not sure of the term sorry) so wear increase and your engine may stop in a short time, when it's too high there is a risk of detonation and destruction of the oil system.
When the oil pressure drop sharply the best is to reduce throttle and fly with cruise settings or even shut down the engine because the temperature could rise very quickly until the engine catch fire.
On the BF i think the oil pressure gauge also indicate the fuel pressure (one of the needle is for oil the other for fuel pressure), as for oil pressure a drop indicate a leak.
So generally speaking a problem of oil or fuel pressure which can't be solved by managing the temperature of the engine is a really bad news and there is little to do but heading for home ASAP.