So, I have a 2001 with the 5.9 and 45K on it. I was driving to work yesterday and I noticed the RPM's were doing about a 200 jump then back to normal at a constent speed. I looked over to the Oil Pressure and it was about 1/3 of the way from 40 to max. Now it always runs at 40 ish. I cheked the oil and it looks fine. Any ideas?? This is my daily driver and I have about a 64 mile commute every day. Most of it is on the freeway. I drive it pretty light footed. So, any help would be great.

 

Anybody?
One thing that I noticed about the RPM thing is that it does it worse the hotter it gets. I live in Phoenix. When I go into work at 6am it is like 85 outside and it is not doing it. But on the way home with the AC going and about 108 outside it does it real bad.