JUMPING Oil Gage

Hey Guys!!! (I am really New)
I'm looking to buy an Astro and when I started it up the oil gage went to 1/4 position however when I gave it a little gas it went to 1/2 position (like half way) and then it dropped back don again.
Anytime I would give it some gas it would go to 1/2 and when I would be like at a stop or at a stoplight it would trickle down to 1/4 again. What is this? Is this normal for these cars?

Also any suggestions for what to look for when buying a car like this.
It’s a 1994 Astro 5 seat.
THANKS
~J

That's fairly normal for any engine. In order to reduce pumping losses, auto makers have been sizing oil pumps more closely to actual flow requirements. This saves a little fuel at idle and on warmup. It also causes the phenomenon you describe. This has been happening since the mid-late eighties at least. The phenomenon is less prevalent if the oil used is in accordance with the owner's manual for a given ambient temperature, and not just what's embossed in the oil filler cap. Although most engines will be labeled "5W-30" the owners manual will show that 10W30 is recommended at ambient temperatures above 40°F. Almost everyone ignores that.

Pretty normal for the 4.3 in an Astro. Now it the gauge starts wildly shaking back and forth that usually indicates the oil pressure sending unit is going south. At least that's what i saw twice on my 92 when I had it.

my 90 did that for awhile, as long as you dont get a thumping noise down low your ok, however, after i rebuilt mine my oil guage would go to 3/4 on startup and never go below 1/2, then i had a thumping noise down low and it dropped to 1/4 and was shaking, well i odont know if the pump went bad, but the skirts on the piston did, so now i am starting over again, so keep an eye on it, like the other guy said as long as its not shaking or bouncing all over the place erraticlly.