the oil pressure gauge pegs over to the high end when the engine is running. on 1994 Isuzu Rodeo

The gauge reacts immediately like there is a short somewhere. How do I determine if the problem is the gauge or the engine sensor?

Asked by for the 1994 Isuzu Rodeo
1 answer 1 comment
DOES IT PEG WITH KEY ON ENG OFF?
The gauge only pegs when the engine is running.