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6.0 L engine runs rough, skipping, surging ???????
Have some trouble with my 2004 F-350 6.0 L it has 115K miles. I have owned the truck since it came off the line.
About 2 months ago the engine it started skipping. When started in the morning it runs rough, with a lack of power, after about 5 minutes it settles down and runs better. It has had the flash that is supposed to fix this, and it helped for about 1 week, then started back doing it again.
After it warms up a bit, it will keep skipping, this will keep up for about 25-30 minutes if you are going steady like on a freeway, but if itís stop & go driving it has continued for up to 45-60 minutes. Once it stops skipping, if you are at steady speed, you can feel it occasionally have a slight surge. This will continue the entire time (up to a 10 hr trip). I drive it mainly alone, but even with a gooseneck horse trailer, the extra load doesnít make it run any worse.
I have run Lucas fuel cleaner thru 3 tanks, 1 tank with kerosene, 2 tanks with Sea Foam, and have changed both fuel filters. We have also had the truck running with the computer hooked up with no codes coming up.
The skipping never gets bad enough to stop the truck, just have tried everything Iíve been able to think of if itís dirty fuel, or a partially clogged fuel injector.
I also have a Hypertech comp chip, could it have a problem? At the first of the year it started the slight surging, and I took the truck in and they ran in on the computer, no codes.
I know itís impossible to diagnose with just my limited info, but any suggestions of what to look for would be greatly appreciated.
Took it to the heavy duty diesel mechanic I use, and took for a test run, then disconnected the EGR valve. When I started it back up it was running rough the whole time, not just occassionally.
Does this mean it is or it is not the EGR Valve??
Thanks again for any input, let me know if you need more information.
Last edited by trucksr4girls; 09-24-2008 at 03:39 AM.