Oil pressure gauge dancing, sometimes.

[rustedthrough]

First highway run on my 2001 ranger showed this strange behavior. Rolling over 65 for more than 25 miles, if I drop to an idle (stop light in East Podunk) the oil pressure gauge swings wildly between 1/3 and 2/3 normal, making the check gauge light come on. If I hold the brake with one foot and touch the throttle with the other all clears up. Shut off the engine and all clears up. What is happening?

 

[cush]

mine used to do that too. freaked me out the first time. i just replaced the sending unit, its less than $10 and it fixed it.