Oil pressure gauge

[zibby]

I have problem with oil pressure. When I start engine that was off for few hours (cold), oil pressure gage shows low. It goes to normal lever after I drive for few miles. During that time H3 feels like 70% of power. Just like any car when you start it up and drive without waiting for engine to warm up. After I drive for few miles everything is ok.
I always wait 1-2 min to warm it up, so cold motor issue is out of question (choke). Also, oil level is ok. It started doing it after I changed oil for Mobil 1 (first oil change by dealer)
So, do you have same symptoms or do I have problem with oil pump?
BTW, I have only 2000 mils.