I'm not sure how long this has been going on, but i just noticed it a few days ago. When i'm cruising along, maybe 2500 RPM in 5th, the gauge needle starts going a bit wacky. The needle will move frequently from about 25 PSI to 45 PSI, only once the car is warmed up (Over 120 degrees). When cold, pressure seems consistant between 40-50PSI based upon RPM. I've heard that these gauges arent that accurate, but is this fluctuation normal?

Using 5 QT's of Mobil 1 10w-30 EP with a Bosch filter. Oil was changed two weeks ago.

 

Replace oil sending unit (oil pressure sensor). Fairly common problem.