Oil pressure sensor
The Helms service manual says that the 'check gauges' lamp will illuminate if the oil pressure sensor reads too low oil pressure. The 'check gauges' lamp will also illuminate in case of excessive coolant temperature. These sensors feed the lamp via the VCM (vehicle control module). There is neither a description of fuel cut-off nor maintenance by the oil pressure sensor.
I'm not as familiar with Blazers but do know that a similar myth regarding Corvettes 'oil cut-off or sustaining the ignition' floats around. And the Corvette Helms service manual clearly shows its second oil pressure sensor feeding the 'check gauges' light via the computer (the other sensor feeds the gauges). I could not find a similar schematic for the 2000 Blazer, only the text description. That description mentions only one oil pressure sensor.
I have great trust in the Helms manuals, having inflicted permanent and expensive damage following the instructions in some less expensive manuals.
2000 Blazer LT, 4.3 auto, 4 button 4WD.