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John Crouch
John Crouch, Ford Mechanic
Category: Ford
Satisfied Customers: 1835
Experience:  22 years of Ford service, and Ford senior master certified in diesel, gasoline and hybrid vehicles
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ford f550: fixes..dealers..occasionally get loss of power..6.0 diesel

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After many thousands of dollars in fixes at various ford dealers I still occasionally get loss of power in ford f550 6.0 diesel 2006

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Unfortunatly, I am not able to access your prior questions so I will need you to give me some information so that I can help you. I can tell you that in most instances a lack of power will either be a boost or low fuel pressure issue. I will guess that you have had all the common repairs done (hp oil leaks fixed, FICM repaired/replaced and possibly egr and eot coolers and head gaskets performed). If there are any codes stored, please list them for me as well. I will also ask you to give me the complete VIN of the vehicle so that I can research it on Ford's database as well. I will also need to know any modifications done to the truck and if it has a aftermarket fuel tank and what body style the truck is (flat bed, dump, etc), the more info, the better.

Customer: replied 4 years ago.
Vin is1fdaw56p46ea33711. This is f550 super duty crew cab with box on it. Last repair in Denver was may 22 this year turbopower, sensor and regular fuel filter change. In Nashville last week oil change and filter. In January had #4 fuel injector replaced. Sometime before in dec 2011 replaced cam and crank sensor. Wasn't sure you can pick up all repairs now since it is no longer under warranty. Mileage about 218000. All other issues should show up with ford since we only use ford for repairs. I had diesel warranty till 200000 for power train. I am tempted to get delete kit for egr if this could be causing the problem. Since it was under warranty wanted to wait. However on some of the diesel forums some members still had issues even after delete
I just looked at your warranty history thru Fords website. I am curious if there are any codes stored in the pcm at this time. Does it run rough when first started and then clear up? If so, then most likely you are looking at some scored injectors that will need to be replaced. One thing I will recomend is to have a mechanical fuel pressure guage hooked to the secondary fuel filter housing (there is a port and your dealer should have the adapters to hook it up) and monitor fuel pressure from the fuel tank while driving when it acts up. Fuel pressure should NEVER drop below 45 psi, if so there is either a restriction, or a problem with the fuel pump. We have also had issues with the after axle tanks flaking internally and clogging up the fuel pickup and damaging injectors. No TSB or ssm's on this issue and no recalls, but I have changed about 10-15 tanks in the last couple of years for flaking and rusting inside the tank. If there are any codes stored, let me know, that will help as well.
Customer: replied 4 years ago.
To answer. It doesn't run rough when we first start if we let it warm up for awhile first. If we turn on the engine and only wait a minute it runs rough. The fuel injectors were tested in January and they replaced #4. The occasional loss of power can sometimes while we are climbing even just a small hill after driving 65 mph. It will lose power on occasion. But also just around town for no apparent reason. It doesn't shake. It is without much power. They said new turbo would take care of this but it is same. Not as bad as before most of the time. A new fuel tank sounds like a huge expense. Btw can you give me an idea on delete kit feasibility As far as fuel pressure gauge wouldn't be able to do that till we return home to Houston next week vhopefully they will know what to do to hook up gauge
Customer: replied 4 years ago.
One more thing. They probably cleared the codes after they put in new turbo. Would not be able to check for codes till next week to see if there are new ones. This is supplement to my prev response to you
the fact that you state that you have to let it warm up for it not to run bad tells me you have some bad injectors. You should not have to let it warm up for it to run well except for very cold weather. I would have them test the injectors really good when you get it back home.
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