Another thing to consider is the fuel heater and prefilter could be causing an air leak and fuel starvation. For me it sometimes caused a low idle on start with a slight haze but on hot days id have no haze. With days of less power and others with more it then got a bit worse where i had a stumble and miss fire on acceleration after sitting for 30 mins.
For me i had a mix of 2 things 1 the prefilter screen was full of crap and the fuel heater was leaking air at the plug probably exasperating the problem of a dirty fuel screen.
Simple to fix either clean or replace the plastic screen, and inspect replace or remove the fuel heater. Removal is simple just unscrew the fuel heater with an allen socket and screw the prescreen bowl back in its place. The fuel heater is simply there to prevent fuel gelling for the types that forget to run 50% mix, no1, or anti-gel additives. I removed it cause none of the diesel tractors or anything i own has a fuel heater and they are fine down to -35Fwith a proper diesel blend or additive so why shouldnt my ram.