I previously thought I had blew my head gasket but upon cheaking the oil, reservoir, and spark plugs I found no signs of a blown head gasket. But my jeep does overheat and blows black smoke. So could this simply be a sensor?

 

Black smoke is usually a sign of a rich running condition. To much gas.
On the other hand the hand the overheating could be caused by so many things.
Hows ur t-stat= are u losing coolant ? Fans are operational ? Waterpump recent change yes/no ?
A little more info will help greatly

 

T stat, idk how it is I have no gauge fOr it. I am loosing coolant. Fans work. And the guy guy I bought the jeep from a year ago said he did that prior to selling it to me

 

Check into where its losing coolant, it could be a leak. Leaking hose, leaking end tanks on the radiator, lots of things. A leak can introduce an air bubble into the system that can cause hot spots randomly, which can lead to over heating.

Not to mention the loss of coolant.

 

Sorry, but it really dosent leak as much as it just boils up and blows the cap of the tank

 

Has the water pump ever been replaced? Has the thermostat ever been changed?

Has the coolant ever been flushed?