P259F code and knocking noise under light acceleration 2014 6.7

OzzyBrad

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Hey All, I need some help please, my March plated 2014 F350 6.7 with 45000 miles and standard tune, has been bringing up code P259F about 6 times now, truck goes to limp mode and can be reset with a restart and fault away it goes, MIL light stays on until I reset it with my scanner or sometimes it goes away by itself, has only been doing it when cold start take off in the morning.
But the other day it did for the first time when hot and made a rattle type knocking noise when the power was reducing, now the knocking/ rattle noise is there at low RPM between, 1200-1800 rpm under acceleration only most of the time, but does go quite every now and then intermittently, I've put some good quality diesel in it and had the injectors checked on a scanner, all test ok and are equal outputs.
it still has the original turbo, Thinking it might need a new turbo to fix the P259F CODE, but the rattle has me stumped, it still has good boost pressures and no turbo noise, intercooler pipes etc look good.
being of such low mileage and has always had its regular services with genuine Ford parts from from new and has just had the latest PCM updates done recently. Any ideas please?
 

6.7Bison

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Did you check the MAP sensor on the top of the engine? I'm curious if the truck isn't sure about the air it has so it is "hunting" a bit with trying to match fuel. The MAP sensor can clog with soot and PCV oil. Easy enough to clean with electronic cleaner and a soft brush. Just don't poke into the sensor too hard as you may damage it. Might save you from replacing a turbo.
 

OzzyBrad

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Did you check the MAP sensor on the top of the engine? I'm curious if the truck isn't sure about the air it has so it is "hunting" a bit with trying to match fuel. The MAP sensor can clog with soot and PCV oil. Easy enough to clean with electronic cleaner and a soft brush. Just don't poke into the sensor too hard as you may damage it. Might save you from replacing a turbo.
Thanks for your reply, no i haven't checked the MAP, will have a look, fortunately that's one of the most assessable sensors to get to, the engine runs fine and smooth however.
i am also thinking the noise is a single injector knock, I,m going to try to turn the injectors off individually with a scan tool to see if the noise goes away.
 
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