new plugs

[Nooby]

I first checked my mpg for 2 weeks of commuting to work, 15.5mpg

then I switched to synthetic oil, ran it for 2 months changed the oil, PVC valve, and spark plugs

I then ran another 2 weeks of commuting to work and my new ave mpg is 18.1mpg

and increase of 2.6mpg,

pretty nice improvement in mpg for 30$ for plugs, PVC, and 10$more for oil change

of course the plugs were original (gap was around .09in) and had 120k miles on it, no missing and can't really tell a difference after replacing them,
the PVC valve still worked but was sluggish when you shook it, I can tell a difference with the new one, it really makes a lot of rattling when I first start the jeep up

 

[tjkj2002]

You should have been on your 4th plug change.30k intervals for the KJ.

 

[loves_off_roading]

The spark plugs make the biggest difference. Before my spark plug change I was only getting 18.6mpg highway. Now I'm getting over 20

 

[Porkchop]

Gota love that pay back on the plugs so might want to keep doing it at 30k.

 

[Nooby]

yup am planing on doing it, I had other issues that kept me from doing it before

 

[kb0nly]

Same here, just did a plug change at 53k, bought the KJ at 45k and just got to doing it after a long winter and no garage, still had original NGK's, they were out to 60-65 on the gap. Put in new Autolite Platinums gapped to 40, gained about 3 mpg and smoother idle. Definitely keep an eye on the plugs!

 

[family KJ]

Here is a plug question for anyone....Changed the plugs and have been getting worse gas mileage?? WTF. Any takers?

 

[CRD Joe]

Real engines don't use sparky bolts. Lol

 

[bmrrwolfe]

Here is a plug question for anyone....Changed the plugs and have been getting worse gas mileage?? WTF. Any takers?

Possibly check the gap?
Haha i don't know what else would cause it to lose mileage?

 

[Nooby]

forgeting to put a few plugs back in

 

[family KJ]

Think it would be a bit worst than 2 mpg less gas

I bought double platinum Autolites, I was told gapping should not be touched.

 

[jnaut]

Here is a plug question for anyone....Changed the plugs and have been getting worse gas mileage?? WTF. Any takers?

Probably not the plugs. Gas mileage has a lot of variance, especially if you do a lot of in town driving and short trips. It's very hard to pinpoint a single thing that affects daily gas mileage. If you check my signature you'll see my mileage trend that I've been keeping for over a year. The really high spikes represent highway trips. I still get just over 20mpg on a long highway trip. But in town? It ranges from about 14-17mpg. I seem to get better mileage in the summer when the vehicle warms up more quickly. Plug changes really made very little overall difference. In fact my overall mileage trend is slightly down.

I keep up with all my maintenance, plug and aircleaner changes.

 

[belvedere]

Here is a plug question for anyone....Changed the plugs and have been getting worse gas mileage?? WTF. Any takers?

How's it running?

 

[KCJeep]

I switched to diamond fire plugs last week and wow was that expensive but what the heck. I am now getting about 187 miles from a half tank of gas with 60/40 city/highway ratio; which is up from the 168-173 I was getting when I changed them to the other platinums the first time, which was about 153 miles a tank then. I was busy last week with this stuff but back in the truck over the weekend. Too bad I can't get them for my rig! So I think they worked pretty well going from 153, to 168 to about 186 miles a half tank now so what is everyone else getting? Ick I hate WiFi sometimes the signal in and out, and in and out, and it's not momma's little squeezbox...

 

[family KJ]

How's it running?

She runs great! Better than before...unless I am just imagining it. I drive just about the same everyday, all city and stop and go. Everyweek it is the same since before I changed them and after. I just don't know.