I've searched on here for a similar problem but couldn't find it. If I missed it I apologize. Here is what is happening. 04 F450 no mods 36000 miles. At about the point where I am down to half a tank of fuel my check engine light comes on. If I switch tanks and drive for 20 miles or so when I restart the truck the light goes away. If I let the tank get below halfway, the truck idles real rough at first startup in the morning. Does this sound like a Cetane problem? Will some PowerBoost fix this? I fuel up at a station that sells a lot of diesel. The only performance change I've noticed when the check engine light is on is the rough idle at start-up. Other than that she purrs like a kitty.

 

Hosshauler, I am going to assume you got your fuel filters changed out every 15000 miles? Drain your fuel/water separator, catch the fluid in an old cutoff 3 liter soda bottle and check for debris and water. If it is there, change filters. Other than that, do you have a tuner or device to read codes? Could be exhaust pressure sensor or injection control pressurs sensor if it isn't the fuel issue.