Just changed out original spark plugs, 180k miles

[mcloven]

my gap gauge only goes to 85 thousandths and most of the plugs were well past that. surprisingly, still ran fairly decent

 

[07navi]

my gap gauge only goes to 85 thousandths and most of the plugs were well past that. surprisingly, still ran fairly decent

Thanks to one coil for every plug nowadays. It boggles my mind how long they last now but they actually start wearing out from day one.

 

[inmanlanier]

I realize we're the non-stuck generation of 5.4s (purportedly), but was there any challenge removing them (other than the ladder!)?

 

[BlueStangGT]

I realize we're the non-stuck generation of 5.4s (purportedly), but was there any challenge removing them (other than the ladder!)?

If it was on the '08 that's mentioned in his sig and he didn't encounter any problems then I'd say it's likely that he did the appropriate preparation before attempting the removal.

 

[Trainmaster]

Many of the 08's (engines with a date later than 10/9/07 on the right valve cover) don't have the two-part plugs. Those are easily changed.

 

[inmanlanier]

With other cars I've learned to wait until misfire (plug or coil) then at that time do all plugs, and if on a rear bank of a transverse - do all coils in the back as well. Any reason I should change with my '011? It sounds like access is not bad and there is limited benefit to changing them early. Thoughts?

 

[07navi]

With other cars I've learned to wait until misfire (plug or coil) then at that time do all plugs, and if on a rear bank of a transverse - do all coils in the back as well. Any reason I should change with my '011? It sounds like access is not bad and there is limited benefit to changing them early. Thoughts?

I would change ALL of them at 50k miles or less. I change mine every 30k miles. they slowly erode your MPG's and HP from day one. I find them easy to change and the stealers charge way too much. Your 2011 has the new style plugs anyway.

 

[inmanlanier]

And you berated me for doing engine oil analysis to extend intervals, save money - saying it was a waste of money - all hogwash. Now you're talking about blowing hundreds of dollars at least twice as often as needed? You're a funny man - talk about wasting money!

 

[07navi]

And you berated me for doing engine oil analysis to extend intervals, save money - saying it was a waste of money - all hogwash. Now you're talking about blowing hundreds of dollars at least twice as often as needed? You're a funny man - talk about wasting money!

Sorry about the oil analysis posts, I wish I never wrote those even though I doubt if they are worth getting 90% of the time. As for the plugs; that whole operation costs me $45 and about 1 1/2 hours time max but I keep forgetting not everyone was a mechanic..............sorry.

 

[inmanlanier]

Apology accepted. I think you may have missed that when I do plugs, I oftimes do coils as well - they can get pricey.

 

[07navi]

Apology accepted. I think you may have missed that when I do plugs, I oftimes do coils as well - they can get pricey.

I never change coils unless one goes bad, my v-10 coils were original with 200k miles on it when I sold it. Worn plugs are hard on coils. The original plugs for the 5.4 were sp507 and they often broke, then they came out with the sp515 which were platinum and harder to break, now they have the sp546 which give no problems. I use the sp515's because I can get them for $45 - $50 online with free shipping and if I change them every 30-40k miles they come out with no problem and work quite well.

 

[inmanlanier]

We had a Kia Sorento ('06) where the first coil went bad at 96K miles. It was easy to swap so I just swapped one. My '05 Ford Five-Hundred on the other hand - the rear bank had a coil go bad at 106K miles - since it's a real pain to get the manifold off (I tried, gave up and had Ford do it - the EGR tube was torqued on so tight I couldn't get it off - very difficult access to get a wrench down there) - I had them change all 3 rear coils and the plugs at the same time. Since all cars are distributor-less these days and the coils are usually on the head, the heat kills them in some cars before the plugs actually misfire (2 instances in my case).

I've not noted degraded mileage with the broader gap from wear. When you get right down to it - all that's happening is the resistance of the gap opening increases over time. Until you reach the coil limitation (higher gap - higher resistance - you then reach the threshold of insufficient spark voltage to jump the larger gap) - you are not seeing any degradation in spark - just a longer one. You know it when the gap is too big or they have fouled because it starts happening with rapid increase in occurrence (at least in our experience).

I'm at 75K - sounds like I'll just keep cruising for a while before I change plugs and/or coils (may never do coils until they fail in this vehicle since it sounds like they hold up).