So a day ago I had my brakes and rotors replaced on 98 cherokee sport by a mechanic friend. I have been plagued by a check engine light for awhile - going off and then back on - informing me of a bad o2 sensor. It had been replaced initially and yet i still get this reading from time to time.

I mentioned to previous mechanics when getting other work done but at those times there was no code registering. They did nothing about it. My friend looked at the sensor and then determined it was merely the fuse despite it not looking blown (his reading said it was). He told me to just go get the fuse at a parts store and pop it in myself. But immediately after he had removed the bad fuse and put it back in, my Jeeps engine temp will shoot up to the red after idling and then come back down after driving for a bit. It didn't do this before he looked at anything. Or maybe the jeep just hit another problem right after driving away. But it seems oddly coincidental.

I know that this could be related to several obvious things other than that fuse, but is it possible that it is related to that fuse? I plan on replacing the fuse tomorrow to see before taking it in to a shop. But any thoughts?

 

Sounds coincidental to me.

 

Jeeps are pretty good about waiting for you to fix one thing before allowing another thing to break.