I emailed the previous owner I bought my 03 SCREW from and asked when the plugs were changed last. He advised "beginning of last year". Is it worth going ahead and changing them since I already have the motorcraft plugs bought??---DirtySCREW

 

well how many miles is that roughly???

id take one out and look at it, if it looks like it needs to be changed change it, if not, well hell i'd probably change them anyways, (especially if he didnt put motorcrafts in)

 

I'd say their Motorcrafts, as he was pretty **** about using MC oil. But who knows, maybe something was on sale when he bought them and he was jsut concerned with MC oil. But I'm like you, I might change them just for piece of mind. Can you advise why Ford has the gap at .052-.054??? Why the range? I believe there is a sticker near the radiator shroud that says the above.---DirtySCREW

 

That's common with all vehicles - a gap range.

 

but how will I know what is best for my truck for power and mileage?? Or does it matter?---DirtySCREW

 

You are worrying about it too much. I would drive it till your mileage started worsening or it started running rough and then put your Motorcrafts in. They are not going to deteriorate on the shelf. I would gap them at 52.

 

Well Bluejay...I guess I am worrying a little too much...but I'm already concerned about my mileage. I know its a TRUCK. But I'd really like to see 15 mpg in the city. I'm at 13mpg. I dunno if changing now would make a difference. I'll probably pull one from each side and make a determination. ---DirtySCREW

 

You have a 4x4 with slightly oversized tires, right? If that is correct, you may not get much better than that. I changed my plugs at 65,500 and had absolutely no effect on mileage or how it ran. The plugs coming out looked new on the tips and the teck said they would have easily gone 100,000.

 

I do have a 4x4 but I have stock tires----265/75R17. They are BFG ATs.---DirtySCREW

 

I have a 4x2, and my truck came with 245/75/17. When I went to 265/70/17, I lost 1/2 mpg. Lost even more when I went to the 305/50/20s.

 

yea....but she looks GOOD!!!---DirtySCREW

 

As I watched my intown/freeway mileage go from 17.2 to 15, I kept telling myself how much I loved the look.

 

The gap isnt that important. I've seen old plugs removed that the gap had grown to nearly .100 that ran fine.

 

You are not going to notice one bit of difference whether you gap them to 52 or 54 or 56. I even doubt if whatever gauge you would use can really tell the difference either.

Bluejay said he saw no difference between plugs with 65k on them and new plugs - you have any idea what the gap was on those used plugs? I'm guessing at least 80........

Your stock COP system is powerful enough to darn near ignite water - it's not like the old days of points and condenser that was quite sensitive to plug gap.

Reality says that you will notice a bigger difference experimenting with different brands and grades of fuel than you will by being fussy about spark plug gap.

 

so with that said, Should I just shelve my MC plugs and WAIT at least another year or so. Again, previous owner changed them "beginning of last year"; and from what I understand its been sitting for awhile as he had a work truck provided to him. --DirtySCREW