I filled up my gas tank this AM, drove 50 miles and saw it was nearly reading empty. I added more gas to the car, but could only put 1.5 gallons in before the machine shut off. I also observed that the fuel gauge moved a lot while I was driving (a little movement up and down hills is understandable, but the pointer fluctuated and stayed toward the lower 1/2 of the gague. I drove mostly freeway miles, always fill up the gas tank to the top, and changed my fuel filter last week. I suspect that the problem lies with the fuel gauge and not the fuel system. Thanks in advance.

I would also check grounds/wiring in the cluster. My 1980 245 fuel gauge reads full regardless of how much gas is actually in the car when the cluster is not grounding properly (which is something I'm still trying to fix.) There is a way to test the gauge, but I don't remember off the top of my head. If I remember tomorrow, I'll post the procedure.

Mike, it has been a while now since I've had the '79's cluster out, so I might be in error to suggest you see if the nuts on the gauge terminals are loose. I'd say the cluster is the place to start, though, just because it is a heck of a lot easier than the sender end. Didja try whacking it?
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Art Benstein near Baltimore