Run a few bottles of injector cleaner through the fuel system and clean the throttle body. These 3.8s eat oil which causes lousy mpg over time. My mpg increased from 15 to 17 after cleaning the system.

 

I have an 07, so it's a 3.8 with 40k miles on it. I do my own oil changes every 5k, rotation as well. I've run 93 the other day to clean it out but my jeep literally ate the 93 so quickly that I soon switched back to 87. I live in New England so I see all sorts of driving conditions throughout the year. I did notice that at my last oil change she seemed to be consuming about 3/4 of a quart over the 5k miles..

Ill try some injector cleaner for now!

 

A higher octane will do more "cleaning" than 87?

 

No it wont clean anything at all lol. Don't wast your money on putting anything more then 87 octane in the 3.8's

 

Hrmm was worth a shot haha. Oh well injector cleaner will be next

 

Search for the throttle body cleaning. And try that. I have the same exact set up except a manual trans and I get 15 around town and seventeen highway.

 

Will do, thanks

 

Octane only affects the stability of the fuel. Higher octane prevents pre detonation. Nothing else. Move to higher elevations, the octane reduces for less O2.
Rule #1 when you upgrade anything, upgrade the line. Even something as little as plugs.

 

Yes, there is less O[SUB]2 [/SUB]; less air in general.
What higher altitude actually does is gives the same effect as lowering the compression ratio, which allows a lower octane fuel to be used.

 

This link will further address the pros and cons between copper, iridium and platinum sparkplugs:


Copper Spark Plugs vs. Iridium and Platinum: Understand for Top Performance - CarsDirect