Over the last few weeks MPG is lower and lower on the same commute drive, the only thing I have changed is the spark plugs with the recommended NGK part #, there are no obvious leaks or oil consumption, what could cause this?

Thanks.

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02 Jeep liberty gasser

For one thing the crap winter gas
I drop about 2-3 mpg in the winter it seems can tell as soon as they bring that stuff out

I am also assuming you got the right plugs and gapped them to the right specs

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MUDD'S MOTORSPORT'S We do IFS lift installs ,
03 OVERLAND EDITION /Kilby-Skidrow-Mopar-4XGuard skids/ 2.5 inch TOTAL CONTROL JBA coilovers -JBA Arms/MOABS-31 FALKEN WILDPEAK AT3W / 4.10's etc, 04 Kilimanjaro Edition loaded, plus 05 KJ limited

Thank You for the quick reply, yes I gaped the spark plugs to the right gap shown on the sticker in the engine bay that also shows the correct spark plugs for the Jeep, I can't recall the part # right now but it is a NGK brand. Just FYI I normally get about 300 miles to one thank driving the same commute now I get about 250.

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02 Jeep liberty gasser

Not to butt in on the thread, but I have been scratching my head for the last few weeks wondering why my reliable 21-22 mpg suddenly dropped to about 19 mpg. Everything is running great, so I bet your explanation is right on.

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--Prof

927/948 OME Springs - Bilstein Shocks - JBA Upper Control Arms - Rage Black Widow Roof Basket - Viper 3606V Alarm System

Makes a difference for sure

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MUDD'S MOTORSPORT'S We do IFS lift installs ,
03 OVERLAND EDITION /Kilby-Skidrow-Mopar-4XGuard skids/ 2.5 inch TOTAL CONTROL JBA coilovers -JBA Arms/MOABS-31 FALKEN WILDPEAK AT3W / 4.10's etc, 04 Kilimanjaro Edition loaded, plus 05 KJ limited

Local fuel supplier probably made the switch to winter gasoline. Add to that, how many of you let your jeep idle even for just a couple of minutes to warm up, where you didn't before?

No warm up for me, stays in a heated garage

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MUDD'S MOTORSPORT'S We do IFS lift installs ,
03 OVERLAND EDITION /Kilby-Skidrow-Mopar-4XGuard skids/ 2.5 inch TOTAL CONTROL JBA coilovers -JBA Arms/MOABS-31 FALKEN WILDPEAK AT3W / 4.10's etc, 04 Kilimanjaro Edition loaded, plus 05 KJ limited

Hook a volt meter up to your O/2 sensors. When they are starting to go out they get lazy. It some times will take months for one to die.

When they start getting lazy the will cycle here and there and have times where they just go dead.

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05 Liberty CRD DD/ski slut
Lifted,hottune,Full exhaust
05 Mitsubish evolution SSL
450awhp/400awtq autocross slut