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Discussion Starter #1
Has anyone seen a decrease of avg mpg on copper plugs I seem to experience hard starts first thing in the morning when it's cold now when its warmed up it starts right away. My average mpg used to be around 26 27 now it's around 24 it could be the increase in traffic here but I can't even break 300 miles now on a tank it seems to run ok I got plenty of power. I HAVE THE PLUGS GAPPED AT MANUEL SETTING AT 0.48
 

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Has anyone seen a decrease of avg mpg on copper plugs I seem to experience hard starts first thing in the morning when it's cold now when its warmed up it starts right away. My average mpg used to be around 26 27 now it's around 24 it could be the increase in traffic here but I can't even break 300 miles now on a tank it seems to run ok I got plenty of power. I HAVE THE PLUGS GAPPED AT MANUEL SETTING AT 0.48
Copper plugs was something I did right after I bought the car, so can't really say. However, I usually average between 26-28 during Massachusetts winter and 28-30 the other times of the year. This is mostly due to letting the car warm up during the cold to thaw ice and let engine/clutch/transmission warmup a bit.

I do have a few other Mods which does also skew my results. My MPG also heavily depends on what mood I am in and how I drive the car, that's why I gave the range.

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Discussion Starter #3
Warming up makes sense I usually let it idle for 30 seconds then drive it maybe still running rich in that warmup stage when I start driving it I also have Manuel I've done the cold air intake delay valve delete rear mount modifyed stock exhaust as well did you also Gap ur plugs to 0.48?
 

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Warming up makes sense I usually let it idle for 30 seconds then drive it maybe still running rich in that warmup stage when I start driving it I also have Manuel I've done the cold air intake delay valve delete rear mount modifyed stock exhaust as well did you also Gap ur plugs to 0.48?
I gapped mine at 45.

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I cannot comment on this either. Car drove better, but I put them in during fall and then the car was sitting shortly after that. Currently reading like 20MPGs because I only took it out rarely this winter and was drove more aggressive than normal, and then let it sit and run in the garage to warm up other times so gas mileage has tanked.
 

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Discussion Starter #7
I made my final determination the ngk irridium ix runn better gapped them to what modern performance said was ideal which is 0.41 to 0.42 I did that and my shifts are smoother and my economy went way up I went up to Flagstaff got best economy yet on this car I'm at 320 miles with a 1/4 tank left it's reading 34 mpg and performance is alot more lively I just wasn't seeing benefit from the coppers my suggestion try the NGKs they are much better
 

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I made my final determination the ngk irridium ix runn better gapped them to what modern performance said was ideal which is 0.41 to 0.42 I did that and my shifts are smoother and my economy went way up I went up to Flagstaff got best economy yet on this car I'm at 320 miles with a 1/4 tank left it's reading 34 mpg and performance is alot more lively I just wasn't seeing benefit from the coppers my suggestion try the NGKs they are much better
I will stick with the coppers for the summer and through a full cycle and see how they do.
 

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Discussion Starter #9
First thing I noticed with the coppers were the hard starts in the morning thing didn't fire up smoothly it choked and slowly turned over my economy suffered I had to baby the thing in order to at least get decent economy with the iridiums it balanced everything out once I gapped them to proper spec
 

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First thing I noticed with the coppers were the hard starts in the morning thing didn't fire up smoothly it choked and slowly turned over my economy suffered I had to baby the thing in order to at least get decent economy with the iridiums it balanced everything out once I gapped them to proper spec
Coil packs are on good? Did you use dielectric grease when you reinstalled the plugs? No hard starts for me, even when it was 18 degrees F yesterday.

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Discussion Starter #11
Yup all the way around I did what modern performance said to gap irridium ix ngks to .41-.42 and wow what a difference in economy performance and shift quality I do not have problems shifting anymore theirs way more engine output and my economy doesn't suffer being on the gas like it did with coppers in

I suffered similar issues with my Subaru these engines don't perform their best on copper plugs my Subaru same thing more pull with irridium plugs they just perform better in these engines

Modern engines I mean
 

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I don't have enough personal experience to talk on this subject, but I don't think most users would agree with these statements. I actually don't think I had any issues starting, only thing my car did not like in the cold was the gear fluid (which I believe you swapped to as well). Starting was just like it was on the old NGKs, started right up. Performance and engine feels significantly better on my 2.4 since those coppers, but cannot speak on gas mileage. I was going from used Irridiums, but still I always felt the car was lacking in drivability (for what it is) even in lower mileage. I did do a lot of different upgrades around the trans (rear mount, short throw plate and shifter, gear fluid, CDV delete) but I could just feel the car was significantly smoother the first drive on those coppers. In another month and a half I will probably bring it back out and actually see some numbers. If my Blazer keeps acting up and setting my wallet on fire, then I might need to take it out sooner.
 

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Discussion Starter #13
See coppers were the very last thing I did after the other mods rear mount cdv delete etc including cold air intake only thing I haven't done yet is my headers and gear oil I've tried both with all modifications and gave computer time to adjust my personal experience I just don't see any gains I see significant loss and I'm also using the used plugs I took out switching to coppers the gap did it in for me showing the improvement

And weather has been warmer lately
 

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What copper plugs were you using?

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Trued both autolite and champion same result
I will keep this in mind as I drive mine. Not saying this is wrong. Can't argue with results, but can argue when there are mixed results. Best thing is to try it yourself and see for yourself, just as you did. Just gotta go with the better option. I don't know what the stockers were gapped at. Maybe if these coppers don't live up to expectations I will try the MPX recommended gap.

Also try to keep your posts together and not back to back. You can click on the three dots at the top right of your post to edit and add additional content if you think of something after. I have merged them as I notice them.This is just to keep the thread count down and avoid having 20+ pages of content if multiple people are multi positng when it might only need to be a 5 page thread.That's a bit exaggerate but you get the point. It's not as strict as it used to be here. Before we would give infractions for repeated abuse of this rule, but I think I am the only mod left on here. I am not even sure if the Admins are still around. Surprised the lights are still on around here lol
 

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Discussion Starter #18
Ok I'm gonna try the coppers again this time i pulled fuse on ESP now every ounce of engine power should get to the wheels without computer interference just disabling that whole thing made a big difference in performance
 
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