Rough idle

[cummins379]

07 Piterbuilt ISX Cummins idles rough after fueling

[tree98]

Do you leave the truck running while fueling or do you shut it off? I had a truck that would start hard (long crank time) right after getting fuel. This went on for a few months, I couldn't figure out what was happening. It would start fine every morning but not if I shut it off to get fuel and then restart. Then I replaced the spin on water separator/filter that has a really thick oring that seals the inner and problem went away. Apparently what was happening is it would get air in the system when the truck was hot and that's why it was so hard to get started again. Actually had nothing to do with getting fuel, it's just that I never shut it off hot unless I was getting fuel. I have no idea why it would always start easily every morning. I know your not having the same exact problem I had but I'm thinking you might also be getting air in the system somehow.