Hello, I need help please. My truck is a 2008 Freightliner cascadia with Detroit 60 series and it's been deleted. I just noticed the past few days my RPam went from 5000 to 1000/1100 while idling and also now to get to 65 miles an hour I have to be at 1800 rpm from 1500 rpm. Anything to be worried about? Any advice will be helpful. Thank you