Mixed feelings about the Jeep already...

[DRamrod]

Hey guys/gals I'm pretty silent on the boards, I usually use the search engine for information about the Jeep. I have the 2006 Limited 5.7l that I just purchased about 2-3 months ago and I'm really NOT that into it. The vehicle works for what it's supposed to. I'm a huge fan of the interior room and all of that stuff. I really didn't intend to keep this vehicle long, nor am I head over heels for it. The BIGGEST issue that I can't stand is the miles per gallon. I average about 10.9 - 11.9 city, my old 5.7l truck (with MDS) was getting 13-15 CITY. The tires are brand new, I threw some Michelin MTX A/T 2's on it recently. The car has about 61k miles, still smells like the previous owner (damn thing can't go away no matter what I do...)

My wife was being awesome and got me some roof-racks for Christmas. I'm not too sure if I should be angry because I'm still not absolutely head-over-heels for this car. Am I the only person having this issue? I'm thinking about putting a 1-2" lift on this thing to help me possibly like this car, but the MPG is so horrible - I want to kick a baby every week at the pump! (kidding). The only way where I might decide to keep this thing longer than 2-3 years is that if I had some real projectors put on this thing. Does the ecochip from autoanything really help with 2-3 mpg at least? If it does, then I'll want make this thing look more like a Jeep.

I'm still not settle with this thing, what all things have you done to help you personalize your Commander to your liking?

[a49erFan]

When you drive a brick you can't expect to get 25 mpg. Take it off road and you will fall in love with it all over again.

[Matt_]

Maintenance ! Do you know the maintenance history? It's due for plugs every 30k miles, so even if maintenance was done, you're due again being at 60k now.

Check the air filter, clean the throttle body, maybe replace the PCV valve.

What gas are you using? Make sure you're running 89 octane. You'll lose MPG with 87 in the 5.7L.

Also, are you running a quality 5W20 engine oil?

Lastly, disconnect the battery and turn the key on the ON position for ~15 minutes. Then turn the key OFF and reconnect the battery. This'll reset the adaptive learning modules so the throttle/shifts/etc adaptive to your driving style.

[DRamrod]

I know the plugs were changed at 40k miles. It doesn't hurt to do them again. I use 87 Octane on the 5.7l because 89 in Nebraska has 10% ethanol and I don't trust it. Not too certain about the PCV. The Air Filter is a new drop in K&N installed 2k ago. The dealership changes the oil. I got them to change the oil for me for the next 6 years (part of the deal) for free.
Does cleaning the Throttle Body really help? Or do you guys spray cleaner on it and call it good?

[jeep5253]

Originally Posted by DRamrod

I know the plugs were changed at 40k miles. It doesn't hurt to do them again. I use 87 Octane on the 5.7l because 89 in Nebraska has 10% ethanol and I don't trust it. Not too certain about the PCV. The Air Filter is a new drop in K&N installed 2k ago. The dealership changes the oil. I got them to change the oil for me for the next 6 years (part of the deal) for free.
Does cleaning the Throttle Body really help? Or do you guys spray cleaner on it and call it good?

Make sure they use 5W20 oil when they change it. The HEMI must have 5W20 for the MDS to function properly.

[07JeepXK]

So the only reason you don't like your Commander is because it gets bad gas mileage?

[Matt_]

Originally Posted by DRamrod

I know the plugs were changed at 40k miles. It doesn't hurt to do them again. I use 87 Octane on the 5.7l because 89 in Nebraska has 10% ethanol and I don't trust it. Not too certain about the PCV. The Air Filter is a new drop in K&N installed 2k ago. The dealership changes the oil. I got them to change the oil for me for the next 6 years (part of the deal) for free.
Does cleaning the Throttle Body really help? Or do you guys spray cleaner on it and call it good?

First thing i'd do is replace the plugs with properly gapped OEM plugs. Worst case, you did them 10k early which won't hurt anything.

PCV valve is ~$20 and 5 minutes to change... swap it out

...sucks about the ethanol. 87 sure isn't helping your mileage at all.

You have an electronically controlled throttle body; don't spray it down with the cleaner. You want to spray throttle body cleaner on a rag/brush and wipe the gunk off with that.

And yeah... is it a Jeep dealership doing the oil changes or a used car dealership? They have to use 5W20

[jeep5253]

Originally Posted by Matt_

...sucks about the ethanol. 87 sure isn't helping your mileage at all.

I have used both 87 and 89 octane in my HEMI and see no difference in mpg, so I use 87 all the time. I also get crappy city mpg -- 10 to 12 mpg.

[Matt_]

Originally Posted by jeep5253

I have used both 87 and 89 octane in my HEMI and see no difference in mpg, so I use 87 all the time. I also get crappy city mpg -- 10 to 12 mpg.

I got notably worse gas mileage with 87, even when tuned for 87, than i do with my stock tune on 89. Its commonly understood, and even the owners manual mentions the possibility of reduced efficiency with 87 octane in the 5.7L. Glad to hear you didn't see a difference though... every engine and driving condition is unique.

I get mid 12s city mpg and have quite a few gas killer mods.

Edit:... pretty sure I got 9-10 mpg while offroading at Rausch Creek lol

[jeep5253]

From the Owner's Manual:

FUEL REQUIREMENTS

3.7/4.7L Engines (If Equipped)
All engines (except 5.7L engines) are designed
to meet all emissions regulations
and provide excellent fuel economy and
performance when using high quality unleaded
“regular” gasoline having an octane
rating of 87. The use of premium
gasoline is not recommended. Under normal conditions,
the use of premium gasoline will not provide a benefit
over high quality regular gasolines, and in some circumstances
may result in poorer performance.

5.7L Engines (If Equipped)
The 5.7L engine is designed to meet all
emissions regulations and provide satisfactory
fuel economy and performance when
using high quality unleaded gasoline having an octane
range of 87 to 89. The manufacturer recommends the use
of 89 octane for optimum performance. The use of
premium gasoline is not recommended. Under normal
conditions, the use of premium gasoline will not provide
a benefit over high quality regular and mid-grade gasolines,
and in some circumstances may result in poorer
performance.

Light spark knock at low engine speeds is not harmful to
your engine. However, continued heavy spark knock at
high speeds can cause damage and immediate service is
required.

Poor quality gasoline can cause problems such as hard
starting, stalling and hesitations. If you experience these
symptoms, try another brand of gasoline before considering
service for the vehicle.