loosing oil pressure

[gtrguy]

I have a 96 Dodge ram pickup. With 128K miles

Today on the way to work, i noticed my oil
pressure guage all over the place.
Staying at 40 for a few minutes, then dropping down
for just a few seconds. Then back up to 40.

I recently did an oil change, but dont see how i could have caused
this problem in doing so.

Any suggestions on what it may be?

Thanks for any help, Brad

[89 iroc-z]

check the oil again see if your low. check the wire from the sending unit (could be loose)as well as the sending unit it's self (it is a ground sending unit so if you have a amp probe or a volt meter you can see if it jumps up and down)if you check that out and it's fine buy a new aftermarket guage and see what the oil pressure is you can get them for $20-$30. if it's still dropping it could be the oil pump pick-up screen is dirty. but to check this you have to drop the oil pan.