Dodge Ram 1500 High Oil Pressure

I drive a 2001 Dodge Ram 1500 Pickup, 4WD, V8, 5.9L with just under 60,000 miles. I was driving my truck yesterday after having pulled a trailer over the weekend. As I was driving through town without the trailer, the "Check Guages" light flashed on and then turned off quickly. At the same time, my oil pressure guage jumped up substantially (from about 30 psi to 70 psi) though it stayed within the safe limit. I noticed that it also jumped every time I hit the accelerator which caused the needle to move up to just inside the safe line on the high pressure side. It was about time for my oil change, which I take care of religiously, so I went ahead and changed the oil and filter. Now, at idle, the guage needle sits about half way between the center line (40 psi) and the high end safe line (? Psi). Usually it's about half way between the low end safe line and the center. I'm using the same oil type and grade, the weather isn't any colder than it has been in the last couple months. The guages all show I'm still in the safe zone but I'm concerned about the sudden jump in pressure. Any ideas? I'm thinking it could be blockage somewhere, stuck pressure relief valve, bad sending unit or a bad oil pump. Not sure how to take care of a blockage or how to diagnose positively. Thank you for your help!