Loss in MPG after new plugs

Kaliber35 · 03-15-2010, 02:23 PM

So, this week I did the following maintenance and repairs to my 05 WK:

New NGK Platinum Core Plugs
New front and rear diff oil (Mobile 1)
New transfer case oil
New rear hub assembly
New power steering pump
New rear brakes

Within a few days I have noticed my MPG drop from 16-17 to 13-14. Any idea as to the cause? I suspect the plugs...

robpp · 03-15-2010, 03:39 PM

do you have the 5.7 V8 Hemi (2005-2008) then it calls for Mopar p/n SPRE14MCC4 (Champion 570) (.045 gap, 16 plugs, tighten to 13 ft. lbs.*)
maybe you should stick to the original copper core plugs?????
I know its a must on the 4.7. or if you have the 4.7, then its a def NO on the platinum plugs.

Kaliber35 · 03-15-2010, 04:31 PM

I have the 3.7

thewalrus · 03-15-2010, 04:38 PM

I noticed this also on my EVIC readout on the dash, it will only last for a couple of weeks with normal driving then you will notice an improvement. No need to worry, the car is just relearning how to drive is all.

Kaliber35 · 03-15-2010, 05:08 PM

Quote:

Originally Posted by thewalrus

I noticed this also on my EVIC readout on the dash, it will only last for a couple of weeks with normal driving then you will notice an improvement. No need to worry, the car is just relearning how to drive is all.

Is this a verifiable fact? No offense...

maxst2 · 03-15-2010, 10:31 PM

It will do that only briefly. Computer will pretty much sort it out in a minute at the most.

You should have copper plugs in it per factory recommendations.

Side note did you check the gap? Buddy with a WJ 4.0L got platinum's for his and couple were off. He ended up taking them back and got coppers after I told him too and he got his MPG back.

dsalinas · 03-16-2010, 02:44 AM

factory plugs are the best for these jeeps, I would stick with copper for sure

03-15-2010, 03:39 PM	#2
robpp Registered User Join Date: Oct 2007 Location: Colorado Posts: 1,068 Profile Gallery Classifieds My Jeeps	do you have the 5.7 V8 Hemi (2005-2008) then it calls for Mopar p/n SPRE14MCC4 (Champion 570) (.045 gap, 16 plugs, tighten to 13 ft. lbs.*) maybe you should stick to the original copper core plugs????? I know its a must on the 4.7. or if you have the 4.7, then its a def NO on the platinum plugs. __________________ Rob 007 Laredo 4.7 FFV 27X; DeBadg'd; Zaino'd; SRT8 Grill, Pedals, Strut; ClearBra; WeatherTech; LED Reverse; HIR Hi/Lo; SS Fog; Stealth Turns; 15% Tint; Stubbie; Rear Spoiler; Magnaflow; V1; 22Elite Console/Visors; Body Kit; Color Match Everything; TintedTails; K&N 63; Front Skid; QuickOilDrainValve; BatteryTender; SuperChips 91; Bilstein; Billet Window Switches; Greasable Addco Sways; RamMedic Hood; Fastman TB; BWoody Links; Kicker Upgrade w/Single Sub; AVIC F90BT Hacked; NeffyWrap ABCD; Putco LEDs; Viper 20s w/255/50; R1 Slot/Dimple w/Hawk Pro Ceramic; Whistler Mod w/FlashTech Halos

03-15-2010, 04:31 PM	#3
Kaliber35 Registered User Join Date: Apr 2009 Location: South Florida Posts: 52 Profile Gallery Classifieds My Jeeps	I have the 3.7