I download the PCM scan and found out what Pid was available , unfortunately they have no GM.ENGINE.FL for the Cavalier.
I have now two problems by using the dash command for Main dashboard, the odometer, and now the fuel gauge, it try it on a 2005 dodge ram diesel and a Buick Century 99, with the same result.
I play with the setting and all are set on SAE.RPM no clue why, I try to set them for the SCRIPT.FUEL.ECONOMY or GM.ENGINE.FTP ( tank pressure) i explain why later, and save it, they all go back to SAE.RPM.
I 'm thinking to re-wire the FUEL SENDER to the FUEL Tank Pressure sensor, since my car is a NON smog, so using the signal and modify it.
Please let me know .