Just checked my van rpm to speed, 4.10 2930-50 @ 60 mph for 15 miles on a hand held diagnostic. 5.9 Magnum 2001. Couple of questions, is this a good rpm for that engines "sweet" spot? Also It's got a lock up converter but the rpm, set at 60 mph on cruise, fluctuates from 1888 to 1955 up and down slight grades but the hand held never goes off 60, is this normal for a new lockup? Take out of overdrive it goes to 2770 rpm @ 60 Thanks
