When an engine is running, an acceptable oil pressure would be: Question When an engine is running, an acceptable oil pressure would be: Answers 10 psi. 50 psi. 110 psi. Explanation Operating oil pressure should be between 35 and 75 psi. Do not operate a vehicle if it has oil pressure that is low, dropping, or fluctuating. This questions appears in the following tests: Arizona Double Arizona Tank Minnesota HazMat Oklahoma Class A Knowledge Test South Dakota Class A Knowledge Test Utah Class B Knowledge Test