CAUSES? High oil pressure

I use high mileage oil in my 2008 with only 34,000 miles. Been doing it since I first got it at 28,000 miles--its on its 3rd oil change, lol. on the other 2008 I got, I switch to high mile oil at 15,000 miles, it has 85,000 miles now and all is good.

I figure te oil is more epa non friendly. Cars today are to last 150,000 miles and still pass smog, so the oil is very low on zinc and other good stuff, if the only says its for 75,000 miles or more, its likely has a tad more of the good stuff in it.

I used 10w-30, the cap says 5w-30 but if you read the owners manual 10w-30 oil is fine and recommended for higher temps. 5w-30 just gives a bit better mpg

My 340 gets 20w-50 racing oil, not street legal since it was first started