I have already changed the plugs in my 2005 5.4L about 20k miles ago. I have 166k on the truck now and have just recently noticed the shudder while in the top gear at about 45-50mph. It happens as I start up a slight incline or just accelerate from this speed. This was happening when I had my factory plugs still installed at about 140k miles so I changed them (broke only 1 and got the broken piece out with Lisle tool) with no real hiccups. The truck ran perfect since then, but I have just recently noticed the shudder again!

All COPs look fine with no corrosion. I have cleaned out the plug cylinders and sprayed some PB in them and removed only the driver's side 4 plugs to inspect them (I ran out of time this evening to remove the passenger side 4). Here is a photo of them:


Now I guess I just need your opinion... I don't think these look bad, do you guys? I will get the other 4 out tomorrow. I bought 8 new plugs (MotorCraft for $13 each!) and was trying to avoid changing them all. I would think that after only 20-30k miles they would still be okay..

Can one of these plugs die within this time frame?

My tentative plan is to hopefully find an obvious bad plug and change only that one and be on my way to return 7 plugs to Advance... Should I go ahead and change them all or would a bad plug be obvious enough to identify? Should I replace the COPs also? Thanks for all the help!

 

If you change on plug you need to change em all and I would not put those used plugs back In if I were you

 

more than likely a COP starting to crap out...also check the condition of your FPDM...

 

Same as techrep, If I had to guess I'd say a COP is going away. I had a similar issue and it wasn't until a couple months after I first noticed the problem that it threw me a code (at least the Predator is good for something LOL). #4 COP and I was good to go. That was maybe 4 or 5 months ago. I thought it happened to me again just the other day but I was thinking it might have been a weird shift or converter lockup coasting along under a light load or some odd happening like that but it might very well be another COP on the way out. To tell the truth, I'd like to change all the plugs and the coils, as well as the fuel filter before I start hauling the travel trailer around this summer. (My '04 Lariat has about 125K miles on it and it's anybody's guess when the plugs where done last, if ever)

 

thanks for the help, whats an FPDM?

 

A FPDM stands for fuel pump drive(r) module. This is what DRIVES your fuel pump and sometimes they can get corroded and all nasty on em. They mounted them to the frame above the spare tire. Kind of on the rear crossmember. It's just a little box with two bolts and a writing harness. Get a Dorman fpdm and it should work.