Oxygen Sensor Circuit (Rich Exhaust). This may of may not be a defective O2 sensor. It may be something else that is effecting the O2 sensor. But considering the vehicle is 22 years old, I would suspect the O2 sensor needs replacing. I would replace the O2 sensor.
G20 is a 3/4 ton and a G30 IS A 1 TON
It is 2701Kg Yes The G30 is a 1 ton.
library
In the alternator
41 to 47 psi
chain
350 4 Barrel is what is in mine
That year sets at ZERO TDC.
Look in the removable housing at the engine end of the upper radiator hose
Depends on overall condition, mileage, options, etc...
I have a 1992 Chevy G30. Takes 10 quarts if the torque converter is empty.
I have the 1987, and according to my manual it's 10,000 lbs. It may have changed by 1991, but this should give you a good idea.