couple of things to check. If you can get to the wiring that leads to the back of the cluster, use a multi-meter to check the resistance of the tan wire. the YJ sending unit is 0 ohms empty, 88 ohms full. if you are not getting any reading or something outside of this range, chances are you have a bad sending unit. from what I've been abel to tell, there aren't any aftermarket sending units that will just drop into the YJs tank.
FWIW, YJs are notorious for bad gas gauges/sending units. Best bet is to fill it up and keep doing so every 180 miles or so. I set my trip odometer at every fill up and figure out my milage.
Originally Posted by Bhelliom
I assumed this thread was going to be something completely different.
I was sorely mistaken