spark plugs: what's your highest mileage, what if never replace?
05-19-2015, 12:33 PM
#1
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spark plugs: what's your highest mileage, what if never replace?
I'm at 150k on original plugs. They are supposed to be changed at 100k, but mechanic said if it is running OK then leave them alone. (I like that advice, but now it is 50k later!). So what is best course of action at this point? Is it OK to have mechanic pull the plugs and check the wear, or is there a risk of breaking it off and therefore better to not touch them?
I basically told myself I'll replace them when I see a drop in MPG. Is that a bad plan of action? I've consistently gotten 15-16MPG for past 12yrs. I can't really judge if it idles rough or not. I'd say it a little rough, but it doesn't jump and snort or coughing up a lung. Is there any drawback to just leaving them in?
I basically told myself I'll replace them when I see a drop in MPG. Is that a bad plan of action? I've consistently gotten 15-16MPG for past 12yrs. I can't really judge if it idles rough or not. I'd say it a little rough, but it doesn't jump and snort or coughing up a lung. Is there any drawback to just leaving them in?
05-19-2015, 12:37 PM
#2
These plugs don't break. That's the newer trucks.
I'd leave them alone till you have an issue. 15-16mpg is good.
I'd leave them alone till you have an issue. 15-16mpg is good.
05-19-2015, 01:09 PM
#5
2003 F-150 King Ranch
I'm at 150k on original plugs. They are supposed to be changed at 100k, but mechanic said if it is running OK then leave them alone. (I like that advice, but now it is 50k later!). So what is best course of action at this point? Is it OK to have mechanic pull the plugs and check the wear, or is there a risk of breaking it off and therefore better to not touch them?
I basically told myself I'll replace them when I see a drop in MPG. Is that a bad plan of action? I've consistently gotten 15-16MPG for past 12yrs. I can't really judge if it idles rough or not. I'd say it a little rough, but it doesn't jump and snort or coughing up a lung. Is there any drawback to just leaving them in?
I basically told myself I'll replace them when I see a drop in MPG. Is that a bad plan of action? I've consistently gotten 15-16MPG for past 12yrs. I can't really judge if it idles rough or not. I'd say it a little rough, but it doesn't jump and snort or coughing up a lung. Is there any drawback to just leaving them in?
05-20-2015, 11:10 PM
#6
05-21-2015, 12:51 AM
#7
Senior Member
200,000k+? Belongs on Ripley's Believe it or Not. Replaced mine at 115k. The gaps were twice recommended but had no oil or serious carbon fouling. I don't have coil on plugs, so that might not make a difference. These were original stock Motorcraft, and I replaced them with the same. Based on what I saw, maybe another 15k or so and the gaps would cause misfires. No change in mileage however.
Last edited by Warspite; 05-21-2015 at 12:52 AM. Reason: Spell Check is your friend
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05-21-2015, 04:10 AM
#8
Senior Member
I changed mine 2 weeks ago. Gaps were at .074-.080 on em. Was causing misfire and really bad mpg. I was getting around 8-10 mpg. Only had 101,600 miles on original motorcraft plugs
05-21-2015, 05:59 AM
#9
Senior Member
mine were .060-.100 ( 4 of them were at .100 if I remember right..) I was getting about 7 mpg now I normally get 14. It would shudder every once an awhile.
Last edited by Fordfan2006; 05-21-2015 at 10:56 AM.
