Oil pressure gauge is low

@ahmadmajrashi there are lots of reasons for this. You will have to go through a plethora of checks to determine what is going on. First off, make sure you have enough oil, the right grade of oil, the right oil filter. Do an oil change with the right stuff. Next could be a bad oil pump. After that it is possible that this is due to worn engine bearings. You will need at least a compression test, and I like to add a leak down test as well. That will at least give you some idea about how worn the engine is.