It really is the weirdest thing. :confused: While I’m sitting at idle in park or in gear the truck surges just ever so slightly. As best I can tell on the RPM scale it’s dropping around 40 to 60 ish rpms for just a second and then coming right back up. It cycles like this between 20 and 30 seconds apart. I don't notice it at any other time but idle. And it does it regardless of if I'm burning diesel or wvo.
I wouldn’t normally be to concerned but I’m taking the family on a vacation/road trip to The Lake of the Ozarks in a week and I don’t want something going out on me halfway through the trip.

Anyone have any ideas as to what is going on? Thanks in advance all…