Atlas

I have an 08 F150 SCAB with the 5.4. My problem is when driving at highway speeds and start to accelerate and if it does not kick down from OD, the truck starts bucking. It has 76k on it. Nothing has been done re plugs or COPs. All routing services have been done religiously, i.e. tranny fluid changes, motor oil and that sort of thing. Is this bucking a bad coil or plug or even injector? No codes come up. Any help would be greatly appreciated!! Thanks.

redfishtd

New plugs and new boots with dielectric grease ,thats normal with your symptoms .

Atlas

Thank you! Based on other threads, I am guessing to go with the Motorcraft plugs? SP515?

tuflehundon

You stated that you have an 08. We have different plugs than the 04-07. They redesigned the heads for the 08's. A few 08's got the old heads, but not many.

Atlas

How do I know if I have redesigned heads? When I look up plugs for this truck, it only gives the option of the SP515...

redfishtd

I would have some 08 people chime in here . I know the heads were revised sometime in late 07 . So yes use MC plugs , clean contacts on your coils ,use very good boots and springs . You may need engine build date for plugs on valve cover .
OEM Coils don't usually go bad so get the corrosion off the hi volt pin . Use belden or oem boots . Dielectric grease on each end of boot to keep moisture out . It is an insulator so I don't like to get it on metal parts much .
Pull the number 6 plug out first, check the kind of boot you have and factory plug . Drivers side, second one in .
You are going to need several different lengths of extensions and a swivel head socket wrench all cheap ones from harbor freight . 3/8 nice size .Get a real good assortment and a 3/8 swivel joint .
Use rubber booted socket for plugs and always start with your fingers, no power tools . Blow dirt out of well and area before pulling .
Pull pcm and bracket to get to 3 and 4 .
Bungees help hold stuff out of way , put card board and cushions on hood latch area you are going to be laying on . Be careful not to break off plugs on vcts, injectors etc . Get step bench in front of truck to get up there.
And yes use a torque wrench set to 25 foot pounds do not go by feel .

Atlas

I have all the tools redfishtd, so that is not an issue. I worry about snapping off one of the plugs and having to buy the lisle extraction tool. That is another c-note I would rather not spend...lol. Will changing the plugs and boots fix the bucking issue I am having and possibly gain a few lost HPs back? My truck is lifted with 35's on it and simply pulling a 10' utility trailer brought my mpg down to 8! DAMN! Maybe that is normal...but seeing the number is horrible. Oh, it was bucking like crazy with the trailer on anything other than a level surface.

techrep

iTrader: (1)

If you have the re-designed heads.. motor build date of 10/09/07 and later, the plugs are SP509 and will not snap off like the old SP 507's. to verify the motor build date look at the sticker on the drivers side valve cover. You will also have brown coil boots vice black.

Atlas

Wonderful...build date is 9-14-07 with black boots.

techrep

iTrader: (1)

Then you will need the extraction tool to remove the SP507's if one breaks and replace with SP515's.. I would replace the boots and springs while you are at it.