This sounds like a dumb question, but have you checked your oil level?
I went somewhere to get an oil change done right after my Jeep had overheated one day, and later on I noticed my oil pressure was jumping all over the place. Since I just had an oil change done, I didn't bother checking the level and just assumed the sender unit was going bad. Then my Jeep started sounding a bit strange over the next couple days... Turns out those bastards put very little (if any
) oil back in the Jeep. It didn't leak oil either, so it was definitely their error. I was so pissed...
So yeah, check your oil level first