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Q: rough idle and black smoke when accelerating on 2003 Ford F-250 Super Duty

2003 F250 all of a sudden has a rough idle and LOTS of black smoke when accelerating. Check engine light is not on. Thought it might be a fuel injector. Does anybody have any ideas?
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Exact same problem... Found the solution
Change your oil type, was running Rotella T 5w-40, this oil foams when it gets hot and causes a misreading for your injectors
Change to Delo 5w-40
Took my truck to Southeastern Diesel and they figured it out
Also check the flex lines on the early 03 6.0L . The coupling to the stand pipe ,which is on the stand pipe get old and the rubber seal wears out,won't build good Highpressure when Idling and starts hard when hot. (Viscosity in oil to low) long cranks to build up pressure. also check for wire chaffing on injector harness.
i would agree. just to be sure, you can have someone do a buzz test to confirm. be ready, the injectors are very expensive.

Try checking your high pressure oil flex lines on your early 03 6.0L. they are at the top of the stand pipe comming out of the HPOP to the head. the pipe comming up from the HPOP has the rubber fitting on it. Use a big fork like for carving a roast to get the coupling appart.the pipes remove from under the rocker cover, with a 3/4 in. socket.(turns Hard). the joint gets sloopy and will not build oil pressure very fast and make idling rough.also long cranks when oil is hot.Also check ijector harness for cheffing under the wire loom. seal with liquid rupper from harbor freight.(used on plire handles). gets really bad when damp out
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