Hey guys. 89 s10 blazer 4.3 2wd. I've been noticing that oil pressure gauge needle is real jumpy and moves alot, mostly when I'm driving and after it's warmed up. Is this a normal thing or should I be concerned? I've had other chevys that have done the same thing but never had a real problem

 

Not sure what you mean but the oil pressure should move with RPM.

You should have at least an indicated 10 psi at idle but the sounds the engine makes is more important. I have a Z28 that shows 0 at idle on warm days but is quiet. Think its a wiring or gauge problem as I have changed the sending unit

 

The sender units can go bad but also as said above, you could have some loose wiring.

 

If you want to know your oil pressure, you need to install a gauge.
In 1990 I bought a new 1991 s10 pickup. The oil pressure gauge was all over the range, mostly pegged at the top.
I took it in for warranty repair 2 times, and they never got it right. My current 1991 S10 gauge bounces around sometimes so fast I can hardly see the needle.