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Discussion Starter #1
My truck has recently started surging frequently, most frequently while taking off from a stop. It will sometimes do it at other times as well when accelerating or at a change in grade at low speed. It will take off, then stop, and then continue doing surging until I let completely off the throttle. It will sometimes die while doing this. The only thing I have done to it recently is replace the U joints, and I don't see how this could be the cause. The throttle position sensor has been replaced, but not recently. It is showing no codes and after I get it going, everything seems fine. Any ideas?
 

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Stuck in Commiefornia...
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No EGR on a 7.3 so that won't be it on a 2001. Basics would be to check fuel pressure, make sure you don't have an issue there. Beyond that, a good scan tool like AE or something like a Scan Gauge II that let's you monitor high pressure oil, injector function, IDM function, and so on.
 

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Discussion Starter #4
I don't have any way to check anything while driving, but I have considered high pressure oil and fuel. I will try to find something to monitor these variables.
 

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Stuck in Commiefornia...
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Watch/search for deals on the Scan Gauge II, they can often be had for as little as $160 and will give you the info you need. Then after using it for diagnostic purposes, it can serve as up to four gauges, plus a code reader, and driving aid if you care to improve your driving style for better mileage.
 
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Discussion Starter #6
Problem solved

Well, it appears that it is fixed. A couple weeks ago my clutch started making noise and went out before I got it home. We pulled it and the throw out bearing blew apart. It did not appear to have overheated, the outer race just came apart in three pieces. New clutch and it seems fine. I guess the clutch was just engaging weird and causing problems. Has anyone seen a clutch do this before, especially one that has less than 20,000 miles on it?
 

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Discussion Starter #7
It started doing it again and actually got pretty bad. It was very difficult to take off on a hill. So I decided to check some easy stuff first and pulled the fuel filter. It looked good, so I put it back in and drained most of the rest of the fuel out. It has been about 4 days and not a single hiccup. I wonder if water or something else was in the fuel filter assembly that was moving on take off, especially on a hill, and temporarily affected fuel flow? Would this make any sense?
 

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Discussion Starter #8
Found it accidentally and fixed

I finally found it, and I would not have guessed it. I thought the FPR could be bad, so I decided to pull it out and check it. It all looked good. I have had a fuel leak from my fuel bowl drain for a while and already had the o rings, so I decided to go ahead and fix that at the same time. So I proceeded to pull off the fuel bowl. I replaced everything and proceeded to replace the seals on the fuel lines. I looked down in the valley and saw this brass spacer laying there. I looked further and saw that the magnet on my IPR was about 1/2" from touching the HPOP and was loose. I fished around, found the nut, and put the IPR back together. All is good. It actually makes perfect sense. Under no load, the magnet would slide back and affect oil pressure if the truck was pointing up hill. The magnet would eventually pull it back on, but would eventually slide back off when the magnet would let off. This back and forth would create the bucking I have been experiencing.

So glad this is fixed.
 

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Thanks for posting the final outcome.!
 
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