C-16 600HP keeps spitting and sputtering then dying..please HELP!!!

so I recently purchased my 1st truck, a 2000 KW W900L with a C-16 600HP 18spd transmission with 3.55 rears. I bought it down in Florida and ran it up to Georgia back in April and parked it at my parents house while I continued to drive a company truck and save some money for some things on the truck that needed to be replaced (cosmetic items) and while I searched for a company that met what I was looking for. well I would occasionally swing by my parents house and start it up and run it down the road and back to keep it from just sitting and while I was away on the road in the company truck my father would occasionally start the truck up and let it idle for a little bit. well while I was at my parents recently I was in process of cleaning the interior of truck and decided to fire the truck up, well it started pretty good and then started to spit and sputter, as if it was running out of fuel!! well i checked the fuel and it was good, so i assumed the fuel filters needed replacing so i purchased brand new caterpillar fuel filters and installed them. primed the truck and it fired up and idled normal. well now the time has come that i'm trying to get everything lined up and suppose to begin orientation with a company next Monday so i put insurance on the truck today and was going to run down and put some fuel on the truck as it is getting low but not extremely low!! i was also going to get 4 of my drive tires replaced as it has 4 new virgin drives and 4 recaps. i want the recaps off and want to match up the rubber. well i started truck up today after not running for a week and it idled good but when I started to move the truck it started the spitting and sputtering again. so i figured perhaps it was losing prime after doing the sitting so i opened the hood and primed it again...fired it up and it ran like crap for about 15 seconds then it smoothed out and ran normal again, so i attempted to move the truck again and then it started spitting and sputtering again...so i primed it again!! got it running again and let it idle for about 15 minutes. idles great but as soon as i put it in gear and start taking off it starts spitting and sputtering. can anyone point me towards a solution or answers on what the problem with the CAT is?? I'm not looking for any bashing because my 1st truck has some age on it or because it has such a large motor in it, i purchased it from a friend of the family who had to give up trucking due to medical problems and gave me a deal that was too great to pass up!! so if all you have to say is negative things that doesn't pertain to my issue then please keep your comments to yourself!! thanks to anyone who can give me good pointers, items to check, etc. All help is greatly appreciated!!!

 

Thanks for the help guys! im going to change the fuel filters today and im also going to check the fuel pressure regulating valve. Just spoke with the local shop and they say it will be Monday or Tuesday before they will be able to get to my truck, so maybe it can be something easy that i fix myself. Thanks again for the suggestions!

 

thanks for the tip superhauler!!