Fuel sending unit/gauge issue? Wrong sending unit?

Well, some or all of that Do a search, there are dozens of posts on this. Start by running over to My Mopar and downloading a service manual, free.

Then take some measurements with various levels of "known" amounts of fuel in the tank. The old factory gauge/ sender tester was a simple box with 3 resistors. About 74 ohms brought the gauge to the empty pin (cold for temp), and about 23 ohms brought the gauge to the 1/2 way point. Somewhere around 10-12 ohms brought the gauge to the full / hot mark. ..........and go from there

We've discussed on here, that repop senders are junk. They are nowhere near the same as factory senders