I noticed when I started and drove my truck this spring I seem to have lost some oil pressure. The oil was changed about 400 miles ago and I haven't done anything to the motor. It used to be about 60 psi when cruising at 2500 rpm but now has dropped to 40 psi, at idle the gauge shows only about 10 psi. I'm going to change oil again and use 20w-50 instead of 10w 30 that I've been using and see if that helps. The motor only has about 3000 miles and I don't know why this problem popped up., Any ideas?