I have an 01 2500

I’m having an issue at idle, it sounds like it has a slight lope. I can see the variation in rpm on the dash and on my display for my programmer. It will only do it if I’m sitting in park. If I have it in gear it will not happen. It started last week. I just changed the fuel filter yesterday and dumped in a good amount of diesel Kleen. My fuel pressure doesn’t show any drop when it lopes. I have my sensor at the bottom of the fuel housing . It stays at 18psi. It will also lose prime if it’s parked up hill with the engine above the fuel tank ,but it has to sit for more than 8 hours before it loses prime. So I just back in my driveway ,and have no issues with prime. Any help would be appreciated 

How many miles on the injectors?

 

What is the exact idle RPM?

 

What is engine load in Park?

 

Like I've seen another member that has zero engine load, idle is like 810 to 816. This is a true sign the injectors are tired.

Well over 100k on injectors. They were replaced at the dealership at 90k. The truck has 236k on it now. 

Engine load at park is 9% and in drive with foot on the brake it’s at 16%.

idle jumps around from 800-850 at times in park, but steady put and doesn’t lope in gear