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mmmm...beer....
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Discussion Starter #1
I've been having a surge/miss under power for about a month now. It seems to be getting worse. I'm currently running Erics x-street, but symptoms are the same tuned or not. Under acceleration it feels like I'm bucking a big headwind with power "surging" in and out. Almost as if there is air in the fuel system. The more pedal I give it, the worse it gets.

FP on my gauge shows 50psi @ idle and cruise. It will drop to 35psi under WOT, but it's always done that when tuned. (I know, ADII is high on my list)

I've never had a MIL, and AE doesn't show any pending codes. At idle, no misfires show at all. Haven't tried logging misfires under power, but I suspect it will come up clean given the lack of soft mifire codes. Is my logic OK here?

I initally suspected an injector going bad. Contribution test is clean according to AE. What else can I do with AE to check out injectors? Tried tuning them off one by one in the system test menu but I don't think I was doing it right as none seemed to have any affect.

I changed the fuel filters, oil and oil filters 2 weeks ago. Oil used was Valvoline Premium Blue 15w-40. No change in FP. The problem got worse after the filter change, but several WOT runs seemed to get it back where it was prior to the change.

With all that said, I'm leaning towards this being either a turbo issue or I still haven't ruled out an injector problem. Along these lines I ought to mention that my boost gauge shows the boost being steady. Although sometimes it will jump to 20psi under WOT, sometimes 25psi, sometimes 30psi.

My question to the 6.0 diagnostic gurus is, where do I go from here? What other things should I be looking at with the AE? The erratic boost has be thinking sticky turbo.

Please feel free to comment on any details I've mentioned. I'm sure I've left out many details, so let me have it!!:D
 

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assuming the egr is still functional it can do weird things if its clogging up. I generally notice it as surging at steady throttle but it could be all or part of the problem, and its easy to check. the other thing that comes to mind is the EBP exaust back pressure sensor. with a tune it might be more prone to clogging and doing goofy things
 

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mmmm...beer....
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418 Posts
Discussion Starter #3
Ah yes. Thank you for bringing up the EGR issue. My EGR cooler was replaced under warranty this spring. I was having white smoke issues so that got replaced along with the latest flash that supposedly takes the EPS out of the loop. None of this actually fixed the white smoke problem. It just "sort of" went away. But that's another story.

My tunes have the EGR shut off. I suppose it's possible for a cooler to go bad in about four months' with the valve shut off but I don't have any other symptoms pointing to the EGR. It's easy enough to check under the EGR valve for moisture. I'll do that as a precaution.

BTW, my EOT and ECT are always within a few degrees of each other. More food for thought....

Incedentally, I'm still under warrany untill December. I would like to be able to present my service writer and parts changer with relevant detailed info when it goes in to avoid them having my truck for a week saying, "We can't find anything wrong." Been there done that......

I'm looking forward to the warranty expiring. Then I can work on this truck myself without feeling like I'm pissing away a warranty.
 

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it really sounds like an injector to me, when my first one went out... it did the same thing.... I changed one.... then i just did them all. has the turbo been cleaned? just some things to check.... it could be a mechanical issue with the injector too....... I am sure one of the pros will chime in......
 

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mmmm...beer....
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418 Posts
Discussion Starter #5
it really sounds like an injector to me,
Well, as it turns out, you are 100% correct.

I quit naming details in my OP because it was getting too long so I left out the part where I ordered a couple of bottles of RevX last week after I came to suspect an injector issue.

I was trying to wait to post my ? untill after I tried the RevX. I should have been patient a few more hours. The RevX showed up about an hour ago.

I poured it in, idled the truck a few minutes, and went for a test drive. It completely cured my surge. The truck runs 100% normal again. It instantly cured the issue. When I got back home it was idling smoother than I've ever seen.

We'll see how much cold starts are improved tomorrow. I've never had an issue really, but it takes 3-4 second of cranking to get it to fire @ ambient temp., whether it be 35* or 95*. I'm anxious to see if this improves.

I really appreciate you input guys! It's almost a bummer the RevX worked so good. I was sort of hoping this thread might gather some finer points of diagnostics using the AE.
 

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mmmm...beer....
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418 Posts
Discussion Starter #6
Oh FYI. When I added the RevX, I was just over 1000 miles on the oil change.

This was my first run with Valvoline Premium Blue. The truck has had Motorcraft from the dealer it's entire life to that point. Right at 87K.
 

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I Just Break Stuff
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2,201 Posts
Rev X is some awesome stuff. Glad you got your problem under control.
 
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