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OK, here goes. I have a 2004 F-350 crew cab dually King Ranch with a 6.0 Diesel engine manufactured in November of 2003. I have been having power issues for a while. Here is what is happening:
1. Cranks great but then has very little power on take-off and while driving. Hot, cold engine or outside temps do not have any effect. Sometimes it clears, and sometimes I can turn off the truck and restart and it clears. Then runs normal. Sometimes no effect. While this is going on there is no extra smoke at all. Looks normal. I drove up a steep hill near home and could not maintain 60mph with the throttle to the floor. I usually can pull my 33 foot 5th wheel up it with ease and maintain 60.


2. Missing sometimes like there is zero fuel getting to the injectors. Usually clears very quickly and only lasts for a 1-3 seconds. This happens rarely, but it still happens.


I have a list of codes that I have gotten. I have cleared the codes and done a couple things. here are the codes I had the other day.
P0069 MANIFOLD ABSOLUTE PRESSURE
P0299 TURBOCHARGER UNDER BOOST CONDITION
P0401 EGR FLOW INSUFFICIENT
P0470 EXHAUST PRESSURE SENSOR A CIRCUIT
P0671 & P0676 (GLOW PLUG FAULTS) I will replace these when I can afford it. Probably do all of them to be sure.
P2127 THROTTLE PEDAL POS SENS SWITCH “E” CIRCUIT LOW INPUT
P2138 THROTTLE/PEDAL POS SENS/SWITCH “D”/”E” VOLTAGE CORRELATION
P2140 THROTTLE/PEDAL POS SENS/SWITCH “E”/”F” VOLTAGE CORRELATION
P2269 (WATER IN FUEL) I have drained pump and need to replace plug and clean sensor. Should remedy this problem.

I replaced the hose (cracked from heat) to the MAP and cleaned the sensor as well as the connection on the intake. Full tank of fuel and 2 cans of Sea-foam. New MAP sensor in the last six months and still having the same problem.
Cleared codes this morning and drove a short distance. Runs good but seems to lag a little on acceleration. Already has 5 codes again.
P0069
P0299
P2127
P2138
P2140

I have been reading many forums and have seen many things tried. I read that my year model truck has a Throt pos sens on the intake. A Ford OEM part that is $150. Something about a throttle body on the intake that has something to do with the EGR. Supposedly there has been a software update that took it out of the process and makes it no longer needed. Not sure what software updates my truck has had. I hope to hook to a friends computer to see if it is up to date and to check voltages and pedal operation. Scan tool I have does not give me enough info.
Several people have said that there is a wiring issue and these trucks are famous for that. People have replaced the pedal assembly with no luck. Best price on pedal assy (adjustable) I can find is $555. I cannot justify that kind of outlay of cash without being sure it will fix the problem.

I have a feeling that many of these codes are tied together because everything I have been reading talks about how so many sensors are tied together to make it run right. Any help with this would be greatly appreciated. If you have any questions, please ask. I have a good knowledge of engines, but all this new stuff on these diesels messes with my brain.
THANKS for any help!!!
 

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I agree that they are likely tied together. It would take an ICBM strike to cause a laundry list of codes like that. First, two thoughts...

1) I get that your truck had an EGR throttle plate. Mine did too. That isn't the throttle to which the codes above are referring. The codes are referring to the accelerator pedal.

2) The EGR throttle plate serves no purpose. You can disconnect it. You cannot guarantee, though, that it is fully open. It would be best to remove the whole throttle assembly and your short intake elbow and replace the whole shebang with a taller '05 intake elbow. Otherwise, remove the plate.

About your problem...

You can go here to get a wiring diagram for your truck:

http://www.powerstroke.org/forum/ge...res-single-page-6-0l-wiring-diagram-pdfs.html

On it, you will see a signal - Vref. It is an internal 5VDC reference generated by the PCM that supplies the MAP, BAP, ICP, EBP sensors and the EGR valve, EGR throttle and - you guessed it - the accelerator pedal sensors. If any one of the sensors or actuators - or the wiring to them - drags Vref down, it causes all of the components that rely on Vref to throw codes. You can check out this link for help addressing wiring harness problems;

http://www.powerstroke.org/forum/6-0-motor-problems/1096562-6-0-harness-chafing.html

I recently posted to a thread that I started showing how you can monitor Vref with Torque. You can see that here:

http://www.powerstroke.org/forum/general-6-0l-discussion/1157409-monitoring-vref-torque.html

Otherwise, tap into it somewhere with a meter and ensure that you have 5VDC. If you don't, disconnect the individual components in succession to try and isolate an offending device. Wiggling wires will help find chafing. Even if you have 5VDC on the IPC/EBP Vref segment, you may not on the MAP/BAP/Throttle side. You will have to investigate somewhat.

Now... it could be something else. ...and I am not a professional diesel tech. But, a compromised Vref is where I am putting my money.

Good luck.
 
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