I'm running the Spectra unit in mine and I must have gotten lucky. This weekend it was reading 1/8th tank, so I stopped and filled up. It took 15 gallons to fill an 18 gallon tank and the fuel gauge moved to full when I was done. I don't trust it's accuracy below 1/4 tank so I try to keep it filled when it gets that low.
That could just as easily be a gauge issue. So I'll ask, Does the needle drop to or a bit below the 'E' at switch off? It more common for the aftermarket senders to make a empty report when only 7 to 10 gallons will fill and get full report.
Where gauge function/accuracy is the fault a restored OEM sender wouldn't cure it, Which is a sales pitch of sorts for the meter match module. I don't run one but from what I've read, It will set the sender to gauge relation regardless which end the fault is on. Good luck to all