03 f250 5.4 jerking at 50+mph

[horse123]

Driving my deceased grandfather's f250 around the other day to move some things, it has 68k on it. Honestly don't think he ever did anything except oil changes. Brakes are shot and I think the transmission is probably factory fill.

Anyway, at about 50mph it starts to jerk like someone is tapping the brakes, it seems somewhat uneven but plenty regular.

What's the deal? It's only a 4x2 so no transfer case.

Transmission or rear diff? Or would it be something else?

 

[otis24]

Could be fuel pump, could need tune up (plugs, wires, rotors, cap).

 

[bdcardinal]

Try the tune-up. You could have a couple coils, especially 3,4,7, and 8 that are fouled out from water intrusion. Also changing the fluid to fresh Mercon V is never a bad thing. Would help rule out any shudder.

 

[Chris142]

those eat coils

 

[horse123]

I don't doubt anyone here, but can someone explain how coils can cause the feeling I described? Interested to know what happens to cause that.

 

[bdcardinal]

It has individual coils and when they go they give up at higher RPMs. The ones on the back 4 cylinders are really common as rain drips on them from the cowl panel.

 

[horse123]

What's the estimated cost if I wanted to fix that myself?

 

[copcarguy]

No doubt: Plugs and / or coils.

I know this from experience with several 5.4's.

First time it happened to me I thought it was a tranny problem too. It'll shake the whole truck lol.

 

[copcarguy]

RockAuto would probably be your best bet to get an idea on parts cost.

 

[Doc8404]

Motorcraft coils (the only ones recommended) are about $45 each

Rockauto or Amazon

 

[ZX11Rebel]

If the plugs and coil(s) replacement doesn't fix it, check the EGR system for a clogged passage or a malfunctioning-sticking EGR valve. Sometimes this cause a "trailer pulling" effect while driving.

 

[Fsharp]

Are you getting a CEL or any codes? I'd think a misfire bad enough to cause those symptoms wouldn't go unnoticed by the computer.

 

[horse123]

No lights.

 

[tig1]

What about torque converter shutter? If the ATF gets too old this can happen.

 

[horse123]

Originally Posted By: tig1
What about torque converter shutter? If the ATF gets too old this can happen.


Read about that... something about it trying to lock up and it couldn't so it causes a jerking motion at higher speeds?

 

[bdcardinal]

Originally Posted By: rsylvstr
Motorcraft coils (the only ones recommended) are about $45 each

Rockauto or Amazon


Yes use only genuine Motorcraft coils and spark plugs. Make sure you do it on a cold engine.

 

[copcarguy]

Never triggered a light in my experience, just shudders the whole truck to scare you to death.

 

[Silverado12]

I agree with doing all the basic tuneup stuff and see if the problem goes away first, including changing the ATF and filter. My wild guess would be a coil pack too. Check www.Ebay.com also. There are deals there sometimes.

 

[Silverado12]

Ebay Coils

There's a lot of these sold. Sure are cheap enough.

 

[Lubener]

Originally Posted By: ZX11Rebel
If the plugs and coil(s) replacement doesn't fix it, check the EGR system for a clogged passage or a malfunctioning-sticking EGR valve. Sometimes this cause a "trailer pulling" effect while driving.


Apply vacuum to EGR while idling and if the engine almost or stalls, the passages are clear. Could be the position sensor on top of the EGR valve.