engine on 1999 Isuzu VehiCROSS

My suv just started making a knocking noise as you increase the gas pedal,it's heard mostly when sitting inside the vehicle.I checked the engine's dip stick and saw no oil then I added 1quart suddenly it was full?? What can this be?

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2 answers
use 93 octone gas
Your vehicle is burning oil, has an external oil leak or the oil level was never topped up correctly after the last oil change.