Newbomb Turk

07 KR SCrew, 5.4L, 148,000 miles...I had started to notice a small "thump" occasionally when getting back on the gas after coasting. Now, I have more of a shudder and it occurs more often. It only lasts about half of a second and sounds/feels like I am running over a rumble strip, then it goes a way. It happens quickly, and then it's gone, but it is occurring more often.
I have read about plugs, coils, transfer cases, transmission, etc., when searching, but never really came across anything that seemed to match my symptoms? Has anyone else had this happen, and is it something that I should be worried about? How do I fix it?

Thanks!

SCORGE

Probably plugs/coils

Newbomb Turk

How would I know for sure? Is there a way to check? I had planned on doing spark plugs soon anyway. Do I need to replace the whole coil, or just the boots/coils? Should I stick with Motorcraft for the coils, or does anyone else make a suitable replacement?

Thanks!

SCORGE

Has that truck ever had the plugs changed before? If not, do it ASAP.
As far as coils.... You have two options.
Replace the boots/springs or buy all new coils. Me... I bought coils off of amazon for the same cost of replacing just the boots/springs and they've lasted me over three years now.

Newbomb Turk

Not sure on the plugs. I've only had the truck for a couple of months. I had planned on changing the plugs after I get back from vacation in a couple of weeks.

What coils did you use?

SCORGE

Amazon specials with the best reviews I could find. I don't remember exactly.

Aeromech

On my truck it was the boots that caused the problem. A set of 8 best quality boots and springs was about $40. I'd like to see someone buy a set of coils for that price. My boots were old and not preventing the spark plug from grounding out which caused a brief misfire. Enough to feel but not enough to latch a code. I used my Autel meter hooked up and reading live data to see the actual misfires as they happened. #4 and #6 were the culprits. Changing out the boots solved the problem.

2006 Lariat 5.4 3V

SCORGE

I bought 8 coils for 37 dollars. They are still working three years later. Most of the time, you probably could get away with a boot/springs change.

redfishtd

Change all the boots . Use a small amount dielectric grease on boot ends . Orig cops don't go bad much clean all terminals on them they get corroded . I am at 193 k and have 7 orig coils , I tried a aftermarket but it failed . Went with lifetime guaranteed from auto zone . Replace all connectors that don't lock on . Clean plug hole out with carb cleaner . Get that carbon dissolved out of there it breaks plugs . Torque all plugs in 25 to 28 foot pounds . Be gentle with plugs and start by fingers . If these are original plugs have lisle extraction tool on hand .
To tell what cyl are acting up Buy 5 dollar torque pro ,android phone does not need to be activated , cheap bluetooth reader-amazon ,under test results it will tell you the raw data per each cyl of misfires that have not reached threshold to set cel .

Newbomb Turk