I have an 04 5.4 XLT scab with 111,xxx miles. I bough it used in 08 with 55,000 miles and I don't believe the plugs have been changed yet. I'll be doing this myself within the next couple of months(due to money). I have already changed the air and fuel filters(she's already running 50% better). The only issues I have is I'm averaging 13 mpg in town (was down to 10mpg) and sometimes when step on the pedal she pauses before taking off. I would like anyone with similar miles and engines to describe the symptoms of a misfire. I haven't had any CELs except 3 years ago and the dealership changed some sensor in the gas tank and that took care of the CEL.

Any kind of info on misfires will help to have a better idea of whats going on and how much more the new plugs and coils will help.

Thanks in advance.

 

I had half those miles and had misfires... Change your plugs. You are more than due. Ford doesn't recommend 100,000 changes anymore so do it now. This is the most common subject here so do some searching before posting.

 

Since it's a 04 they could break off good luck

 

For the record, I never had a CEL when I was misfiring. And it was ridiculous. Bucking down the highway like a fool. You are due for plugs so do them.

 

X2 when my coils were going bad it would shake and buck real bad