93master

On my 93 the check oil light was flashing on and off everyother time i would start the truck. Then after about a week of that, it flashed on every time i would start the truck. I have checked the oil countless times, and even added oil (5w of course). And now the light is still on. My oil pressure guage still reads in the normal range. For those who have a 93 the needle is right on the "R" of the word normal. It used to be higher around the "M." Could this be a oil level sensor problem? Anyone please get back to me.