2002 Trailblazer when you are at a stoplight or just in park the oil pressure gauge will sometimes go up and down from 0 to 40 and the check gauges light will come on breifly no codes pop?

Answer 1

Answer 1 - Fluctuating Oil Pressure Gauge IndicationI am not familiar with your particular vehicle, BUT...

Usually fluctuating oil pressure during idle indicates that the engine idle speed is fluctuating and may need to be adjusted to manufacturer's specifications. Sometimes, this is an indication of wear in an engine.

While the check engine warning lights are ON, indicates that during that time the engine oil pressure is below the manufacturer's recommended "safe" level.

Although sustained low oil pressure can damage an engine, during idle, brief, intermittent, low oil pressure excursions do not harm the engine, but do suggest that you have the low oil pressure issue "checked out" by a qualified automotive technician.

If this problem occurs at normal driving speeds, then you either are low on oil in the engine, or have other problems which could be hazardous for the health of your engine.