shawn 84&92

My idle and oil pressure gauge fluctuate at times. Yesterday the car was idling while I was putting on the top and the check gauges light came on. All gauges looked good, and i gave it a little gas and it went away.
I have had other times when the check gauges light came on, when the oil pressure gauge was fluctuating. Is this common or a concern? I hav e read about oil sending units being a common replacement item, hoping that is all it is.
Thanks for any input,
Shawn

Z51JEFF

I have the same issue on my 91 with the oil gauge when driving on the freeway. Oil gauge jumping around a bit.

A26B

Oil pressure is monitored by 2 different devices,

1. the analog gauge utilizes a sender for its signal and is positioned vertically near the oil filter.

2. low oil pressure indicator (red light) is monitored by a switch, located under the oil filter & a little towards the firewall, on the oil filter adapter.

Oil pressure gauge fluctuation is usually caused by a faulty sender, frequently accompanied by oil in the electrical connector.

A low oil pressure indicator light may also be a faulty switch. They are prone to leak, leaving puddle of oil on the ft-right side of the engine.

If you are having idle fluctuation that drops below 600 rpm without dying, the oil pressure may be low enough to trigger the indicator light.

In any regard, I recommend removing the oil pressure sensor & plumbing in a real pressure gauge to observe when cold & hot, during fluctuating idle and at about 3000rpm, both hot & hold.

Hot oil pressure at 650~700 rpm idle is OK at 20+psig.

shawn 84&92

Thanks, great info! I will look at that.
Shawn