I have a 98 f150 5.4 v8 about 178,000 miles. On thanksgiving my only day off I changed the plugs, well just the 4 on the passenger side actually. (Ran out of daylight) Everything was well until yesterday. I noticed when I accelerate over 40mph my truck hesitates or stalls, kind of like a stuttering effect. When I accelerate over this speed it begins to stutter as I let off the gas slowly it stops, as I give it more gas it starts again. Any suggestions will be very helpful. Thanks.

 

what kind of plugs did you put on them? did you make sure they were gapped right?

 

what gap did you set your plugs to? hopefully you didnt just throw them in the truck as they came out of the box

 

motorcraft plugs, yes the gap was set to truck specs.

 

if it was me, i would finish the other side and see how it runs

 

x2 and make sure all those wires are on tight.

 

do the symtoms i gave sound like misfiring to you guys?

 

well you have 4 old plugs, and 4 new ones, the truck doesnt really know what to do, so yes, but i dont think you have a problem other then half your job is done

 

With only one side replaced... sounds like the old plugs are not performing at the same rate the newly replaced ones are. The one time I replaced only one side on an engine... let's just say... I went to the store pretty darn quick to get the rest!

 

You screwed something up on one of the coils you already messed with - I would go over your work. It shouldn't be doing that. One of the springs aren't right..Or you tried to wash something..

 

Yeah it sounds like a coil is loose or not connected properly.

 

i dont think just changing 4 would creat that. but i would go ahead and replace your plug wires. sounds like one of them got damaged when you changed out the plugs. this happend to my 96 cobra when i changed mine few years back. car would stumble and fall on it's face whenn i tried to accelerate. 135 bucks later with the wires it was brand new again.

98's didnt have individual coil packs, right? if not then get new plug wires!

 

He has a 5.4L - All 5.4L have individual coils. There not called coil pacs. A coil pac runs 4-6 cylinders. He has COP's (coil over plug)

 

damn, thanks. i didnt know they were running those back then. but then again i really dont know too much about ford trucks, just the stangs. sorry for the bad intel.

 

No problem. Inaccurate info will get corrected around here . A great way to get educated.

At times, you may even be hammered for spelling and grammar