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I just bought my truck about a month ago and so far have loved it other than a few issues i have had with it. It is a 2008 F250 With the 6.4 and a zf6 transmission. A week ago while doing about 300 miles of freeway driving and the truck started to shudder over about 2K RPM, I thought it was plugged fuel filters, so 3 days ago i replaced the Fuel filters, and everything seemed fine, but it was only getting up to 30 PSI of boost. Then this morning while i was driving into work i noticed it wouldn't go above 10 PSI ad that was it, other than one pull when i was getting off the freeway were it went up to 20 lbs of boost. What kind of issues could be causing this? i hooked it up to my diagnostic computer at work and it isn't reading any codes.
 

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What did the fuel filters look like? What did the fuel bowl look like? Hopefully no rust/corrosion/deposits of any kind. Many others state to look into the boost pressure sensor to see if it's working or needs replaced. EBP I believe it's called. They get gunked over time.
 

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What did the fuel filters look like? What did the fuel bowl look like? Hopefully no rust/corrosion/deposits of any kind. Many others state to look into the boost pressure sensor to see if it's working or needs replaced. EBP I believe it's called. They get gunked over time.
Both of the filters were pretty black, i have pics if it would help, the frame rail filter had a clean spot on top but other than that they were black, i didnt see any sediment in the bottom of the fuel bowl though the previous owners used pipe dope tape on the threads of the fuel filter caps.

Would the boost sensor throw a code, and if it was faulty would my dash still show boost? it doesnt feel like its getting boost, it just feels sluggish
 

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Well that's weird that he would have used pipe dope on the threads. Were they OEM Motorcraft filters you pulled out and put in? OEM filter caps as well? I've changed my fuel filters twice at 15k miles. Each time they have been barely discolored at all, an off white. I would wonder how long those filters had been in there or if the trucked had old/bad diesel in the tank. I don't use top tier diesel, just whatever is cheap and have never had a problem.

The fuel/filters wouldn't cause the low boost problems though most likely. Do some searching in the 6.4l forums for low boost, no boost, boost problems, EBP, etc. I've seen some recent threads similar and they haven't gotten codes for it.
 

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I am not sure how long they were in there, ijust bought the truck a few weeks ago, it was an old oregon forest service truck, it still has the toyo M-55s on it. i will try and do some searching, i am just worried about it going to be expensive to fix, i was recently in a motorcycle accident and the medical bills wiped me out.
 

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Here's a couple of threads that said cleaning/replacing the EBP sensor fixed there no/lack/fluctuating boost problems. They are for 6.0l, but should be the same for us 6.4 guys.

https://www.powerstroke.org/forum/6-0l-problems-forum/397666-ebp-sensor-cause-boost-problems.html

https://www.powerstroke.org/forum/6-0-motor-problems/217297-exhaust-back-pressure-sensor-bad-dirty-causing-tons-boost-no-power.html

https://www.powerstroke.org/forum/6-4-motor-problems/1294698-6-4-no-boost-help-lost.html

There's also some youtube vids showing how to clean/check/replace it and the symptoms of a bad one. Easy cheap fix hopefully!
 

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Alright, come monday ill see if i can get my truck in for some shop time here, i work for Cadillac and should be able to get it in here see if i can clean the sensor maybe get a new one at a discount through parts.
 

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Discussion Starter #8 (Edited)
Got a scanner that was able to read codes that a hand held scanner couldn't and i have two codes a P0703 code for Brake Switch B circuit malfunction, and code P1876 for transfer case 2 wheel drive solenoid open or short to ground, do you guys think either of these will cause a boost problem? from what i'm reading the 0703 will **** with the torque converter on automatic transmissions and wreck havoc.

UPDATE: Cleared the codes and now normal boost is back and my cruise control is working again, any ideas if there is some sort of common problem causing a short in the brake wiring?
 

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Don't worry about the brake switch DTC unrelated and just a nuisance code i'm sure every 6.4 owner sees everytime we pull DTC's from our trucks. P1876 is a solenoid code that will cause a shutter as the solenoid is not opening or closing correctly. Your truck should have the 5110R tourque shift transmission???? I know from experience bad solenoids will cause drive clutches to burn and cause huge transmission repairs. This would explain shutter but not boost loss. You need to invest in a monitor that will give you real time access to your engine PID's. Your compound set up should be 2:1 boost to back pressure. If your boost back pressure is compromised by a bad sensor or gunked EBP tube the truck will not run right. The EBP sensor is one of the big players in how the engine will receive the correct boost/fuel. If you did filters and EBP sensor and the truck still has issues you need to look at what your fuel rail pressure is doing during low boost or shuttering. Hope this helps
 

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Download Forscan -- PC version is the best, but whichever platform you can use to pull codes and take readings -- Torque Pro works well as a monitor

Curious why pipe compound was on the filter threads -- sealing issue I assume -- if the previous owner was having fuel problems, maybe you need to investigate if there is air getting into the fuel system
 
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