Bucking at high speed 2005 6.0

[Oicdodd812]

2005 f250 6.0 Harley edition bone stock with 140000 miles. I've got a bucking issue at high speeds around 75 that goes away when you tap the brake enough to lock the torque convertor. I've seen a similar post on here about this buy can't seem to find it. And help would be greatly appreciated. Thank you on advance.


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[Oicdodd812]

Damn autocorrect. In advance. Lol


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[shawnb99]

torque convertor slippage.... or fuel pressure is dying off.

[Oicdodd812]

So blue spring update first then I'm pretty much left with torque convertor. Is there anything I can do to prevent convertor slippage? Is this a sign of a failing tq? I'm pretty out dated when it comes to trans issues. Thanks for your input guys. I really appreciate it!!


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[Oicdodd812]

What can be done if its a torque convertor issue. Is there a PCM update or is it a mechanical issue? Thanks


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[Gearhead2012]

Does it happen under consistent throttle, or while going uphill, downhill, while accelorating to 75mph, or only once cruising at that speed? When hot, when cold...all the time? And is it throwing any codes? Thanks

[Oicdodd812]

It's a new truck so I haven't gotten a monitor to check codes yet. But soon! It does this when engine is warm and cruising speed is constant around 75 ish. If I hold a steady pedal it will do it and if I tap the brake just enough to engage the brake light it shifts up and goes away. Most of the time the shaking happens or is more noticeable going up an incline but this is kind of intermittent.


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[Gearhead2012]

I bet you have an injector out, or going out. You'll feel it more when the torque converter locks up. Get a diagnostic tool to read for codes. Not all codes will come up with those cheesy actron scanners. I have one, for use with other cars, but they don't tell you much on these trucks. Codes have like a rating system to them, not all codes will throw a check engine light right away. Or at all. Good scanners will read more of these codes. There's a theead called monitoring the 6.0 I'd recommend reading if you're a new owner. If you're handy enough to fix things things yourself, and plan on keeping the truck a while look into auto enginuity, they make a scanner diagnostic tool everybit as professional and powerful as the dealer scanners. It's 250 for the basic obd2 setup, and the ford ad on is like 220 additional. If you figure most shops will charge you 120-200 just to tell you whats wrong, it can pay for itself quick. I don't work with ae or anything, i actually dont even have one...just spent the last several hours reading about them though. It's on my list of things to get. Anyway, get that figured out, bad to ride around on a missing injector. if thats what it is. Good luck.

[Oicdodd812]

Thank you so much for the help. I will get the codes checked ASAP! I do plan on keeping the truck and working on it myself so I will definitely look into that. Sounds like a very powerful tool to have! Ill keep you informed on what I find because I may need some more help. Lol. Thanks again!!


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[Gearhead2012]

Yeah good luck, keep us posted on what you find out. Mine does that now, and needs 2 injectors, it was just a very faint shudder most noticable when the converter locked up after about 50mph, but now it's horrible.

You can do all sorts of stuff with the auto enginuity software...cylinder contribution tests, buzz tests, check FICM (fuel injector control module)voltage, all sorts of stuff. I'll also ad that if it is injectors, there's likely also a problem with the ficm. in fact, it could just be a faulty ficm at this point too. Research how to check FICM voltage, its really easy, should be 48v, no less than 45, ever. Your FICM can kill injectors, your batteries can kill your FICM, so kinda need to keep an eye on everything and make sure it's all within spec periodically, again, why monitoring is so crucial.

These trucks are so finicky...why do we all love them so much?