TurnKey

Okay guys a bit, scratch that, total newb here, been doing a lot of reading and searching and thought I'd just bare my soul to you guys and ask what you think.

Purchased an 06 F150 5.4 with 54k miles on the clock. Real nice truck overall but have an issue.

1. Under hard acceleration it breaks up, the harder you mash the throttle the more it breaks up. If you're easy on the throttle it runs perfect, even if you're on the throttle say half way it runs pretty well until upper rpm but in the upper rpm the more you get into the throttle the worse the condition.

Now I know at 55k I should change the plugs if for nothing else than to make life easier getting them out before too much carbon build up so that's on the list for sure. What Plugs should I use?

What do you think is likely to be causing my problem? I know it's not likely the plugs (that I will change anyway) and am leaning towards the crank position sensor but have heard a place or two it's rare that is a problem.

I'll also change the fuel filter, just installed a new air filter, have three cans of seafoam (a bit more than 1 ounce per gallon) in with a fresh tank of fuel now. Plan to clean the throttle body.

So of course I'm hoping this tune up will fix my issue but does anyone have any insight into what they think the culprit is? Do I just need to get to work on this stuff or is there one thing I should tackle first? Extra time is pretty short for a few weeks and I'd prefer to get this issue fixed if its more like one thing as I won't have time to do it all for a few weeks.

redfishtd

Your plugs and boots are the major source of misfires.. Do them right use oem plugs .This engine requires spark plugs and boots to be perfect .
Blow out spark holes before soaking with pb blaster or carb cleaner . Read factory TSB on plug removal .
Clean carbon out of tip area with carb cleaner .That carbon will damage new plugs and cause problems . Always use new boots . Clean tips of cops . Use dielectric grease on boot ends .
Torque wrench them in to 25-28 pounds . Double check them .
If you let it keep misfiring you may damage cats and thats expensive .
Seafoam really isn't going to do much good if any .Not good for cats .
Take your time and do it yourself . Yes pull the PCM and bracket of to get to 3 and 4 .

nrivera04

Motorcraft plugs, but at 54K, the original plugs are likely still in there. You should rent, borrow, or buy a lisle tool if you're going to change them out yourself. Most also recommend a bottle or two of seafoam or trchron cleaner right before you change them. Make sure you change the boots and springs on the coil packs as well and use a tad of dielectric grease to seal out moisture.

Hard to tell what's causing your issue. I would only be suspect of the crank sensor if you were getting a check eng light. Do you have a light on and if so, have you pulled any codes?

Most issues with this gen tend to be misfire related. I'd start with plugs and a fuel filter and see what that does for you.

FrozenTundraGuy

I have an 06 and had my plugs changed a@55K. No misfires, just wanted them done early. I found a Ford dealer that changed them out for $300-total price. I ran several tanks of Berryman B12 before the change, all came out w/o a problem. Shop said my coil packs were OK. The plugs were surprisingly worn-wouldn't have lasted much longer. Good Luck.


PS-Keep a eye on your oil level-these trucks use some oil between changes

techrep

iTrader: (1)

Check the condition of your FPDM also

TurnKey

Thanks for the responses guys, is that the fuel pump driver modulator? Had to google that one

TurnKey

The light will only flash if I stay in the threottle for a while and keep it misfiring, otherwise no light.

BadFish523

I would start with boots and springs on the coils. If that doesn't do I then plugs. Or if you want do them both while you're in there.

SCORGE

Yes. Located on the cross-member above the spare tire. Common victim of corrosion

redfishtd

That lisle tool is a big help for broken plugs , I broke 2 originally ,some guys break them all . I bought my own, some box stores may have them to lend .
Been so long since I have dealt with a first time change on this year of truck ,I plumb forgot . I do like techron fuel cleaner its good stuff . You don't have to use nickle anti seize if you use new style plugs and clean tip area carbon out .It was a temp fix until new plugs came out, A-seize can cause problems itself . . And another common failure is plugs backing out because they weren't torque wrenched in to 25-28 pounds .