The fire dept I belong to just got a 923 with the nhc 250 engine . It’s out forestry truck. We have a 600 gal tank on the back and some hand tools. We only use the truck prob 5-6 times a year and we don’t go far with it . Was wondering what’s the quick and easiest way to gain a little my hp with this engine ? If I need to install a egr temp gauge I can do so to monitor the temp . Truck goes fine straight down the road but the hills it down shifts and goes pretty slow. We have changed all filters on truck