04 f550 6.0 diesel after fuel filter change start up stumbles alittle....
i wrote a fuel filter change that i did on this 04 6.0 diesel f550 for my friend. so changed both fuel filter and put two new batteries in. it fires up but for about 5-10 seconds it stumbles like its clearing its throat. not a stumble like its going to die but alittle rough idle and then idles out fine. then runs fine after that. before i did the fuel filter change i dont recall that ever happening. any ideas?
I think I'd pull the upper filter and make sure it's not draining back down. I don't know why that'd cause stumbling at startup, though. You may have nicked the o-ring on the lower filter, which can cause air to be pulled into the system. But again, that should cause problems all the time, not just at start.
I think I'd start checking the FICM voltage, operation of the EGR valve and check for codes. It could be just a coincidence that the problem started now.