So I'm getting my plugs replaced in my 2006 XLT 5.4, 88,000 miles, in a couple of days. $350 out the door IF the plugs cooperate. Not holding my breath. I do have a couple of questions though.

1. Should a prep the spark plugs and shoot some PB down the holes the night before? (I will be driving the truck to the mechanic the next day)

2. Will dumping some Techron, Seafoam, etc in the tank help any?

3. Any particular plug to replace with?

4. I'm getting the low-speed misfire "stutter". Should I have the COPs replaced at the same time? I could do this myself later I suppose and save a few bucks......

Thanks,

 

Run some Techron through it. No Seafoam, can clog up the cats. Go back with Motorcraft plugs, with high temp antisieze on the shanks, none on the threads. Change out the COP boots. If they use an impact for the removal, almost never a breakage.

 

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Inspect the coils boots when you have them removed.


You trying to tackle the job yourself?

https://www.f150online.com/forums/v8...s-55-56-a.html