So I went to the jy today to get thecoolant hose fitting that comes out of the tensioner, on my way back i noticed my temp going from 150 to 200 back and forth while driving, theres no coolant hence me getting a new fitting, the old one lost the gasket and cannot for the life of me find a new one so got a different one with a gasket on it still. But either way is my temp sensor just not reading right thanks to the coolant issue or is it just shot from who knows what?

If your low on coolant then it'* likely your getting coolant coming threw uneven, so a blast of hot, then cool, then hot. Get the problem fixed and it should be stable.