Hello I have a 98 Dodge Ram 1500 V6 2WD. The truck starts and idles fine, on a flat road its great but when it comes to any type of hill or incline i start to lose power and i mean ANY climb. I have replaced my cat, wires, plugs, cap/rotor, still no difference. My truck has 155k miles on it, when i start the truck in the mornings I can hear a loud hiss sound like it’s trying to suck a ton of air but after the truck warms up the sound is gone... any help would be greatly appreciative

 

that's pretty common, especially with a V6.
have you got larger than stock tires? those hurt.
have you fixed your plenum. that hurts too.