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shorty
Dodge Dakota
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1/23/2006
23:11:12
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 Subject: bad gas milage and k&n filters
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I just bought a 2000 dakota 4.7 v-8 I get about 13-14 mpg with 31-10.5/15 tires so I put a drop in k&n filter in it and it's dropped to about 12.6 mpg I thought better air flow got better gas milage also does dodge come with 30,000 mile or 100,000 spark plugs I think that may be a problem too any other suggestions also any modifications anyone recomends to do to this truck I would love to listen to them all thanks shorty
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Dan M
Dodge Dakota
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1/24/2006
06:34:49
|  RE: bad gas milage and k&n filters
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More air can be a good or bad thing. I noticed when I put a K&N in my old 95 I drove it harder. This can have a negative impact on gas milage.
- Dan M
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Tired
Dodge Dakota
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1/24/2006
14:31:49
| RE: bad gas milage and k&n filters
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Sounds about average. I have the same truck and get worse gas milage and I don't drive that hard anymore either.
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Luke
Dodge Dakota
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1/24/2006
15:29:14
| RE: bad gas milage and k&n filters
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My 03 dak 4.7L got worse gas milage with a k&n also. I have asked around and the best explaination i got was that the mass air sensor detects the increase air flow and the computer therefore delivers more fuel. The result is better performance but a little worse gas milage. As far as the sparkplugs, I think they are supposed to be 100,000 miles but I got a misfire code at 40,000. So, i changed them out and the old ones were shot. I went with the bosch plat.+ 4. I have 4x4 QC with a 3" body lift and 32" tires and I get 14 mpg city and 17 mpg highway. That is driving pretty easy. Hope this helps. Almost forgot, I also have a superchips programmer with the 87 oct program in.
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Dark Jedi
Dodge Dakota
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1/24/2006
21:27:48
| RE: bad gas milage and k&n filters
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no the plugs are not 100,000 miles. these are reg champion copper plugs and should be replaced at 30,000 miles. this comes from my owners manual for a 03 dakota. it also says plays are not good for our coil over engines. but as posted here so many people runs plats with no prob yet.
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shorty
Dodge Dakota
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1/24/2006
22:24:31
|  RE: bad gas milage and k&n filters
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Thanks for all the advise you've been a big help
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Kowalski
GenIII
1/25/2006
17:12:14
| RE: bad gas milage and k&n filters
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Same truck here too, but better milage. Stock was 15 without even trying for milage, no drop with K&N, increase to almost 16 with 4.10 gears. I'd start with the plugs.
Lead, follow, or get out of the way
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choochoo
Dodge Dakota
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1/25/2006
20:20:02
| RE: bad gas milage and k&n filters
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2004 Dak 4.7 auto 5spd 3.55 gears 4x4 QC
Leer cap 38 psi in tires K&N drop-in
Best mpg in summer, no wind, 60 mph, cruise on is 21 mpg - checked doing the math
I prefer Champion copper plugs, changed every 25k
Beware when changing axle gears or tire sizes that you recalibrate your speed sensor, or else you will think you are going further than you really are. This can make you believe you are getting better mpg. Regardless of what others say, usually closer ratio gears give better mpg.
There is so much bottom end power in our trucks that unless we tow heavy loads, 3.55 gears are well spaced for both towing and mpg.
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shorty
Dodge Dakota
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1/25/2006
21:55:11
| RE: bad gas milage and k&n filters
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I wasn't planning on changeing axle gears I don't tow much just a snowmobile/4 wheeler trailer and that doesn't weigh much so I have no reason to change that but thanks for the tips I can tell someone else if the situation comes up
shorty
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Kowalski
GenIII
1/26/2006
17:13:44
| RE: bad gas milage and k&n filters
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choochoo - there's no need to recalibrate for speed for us with a gear change since the speedo is driven off the rear; not the tranny.
I think you mean numerically lower gears (like 3.55) rather than "closer". That's the conventional wisdom; but several of us have seen mpg increase with the drop to 4.10. The 4.7 must make power a little more efficiently at slightly higher revs.
shorty - your gears are fine for what you're towing. I pulled 5000 lbs no problem with the 3.55, changed mainly for performance.
Lead, follow, or get out of the way
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choochoo
Dodge Dakota
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1/26/2006
23:33:21
| RE: bad gas milage and k&n filters
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Yes Kowalski, that is what I was trying to say. "Closer" gears to me are a smaller mathematical number. I have read other posts as well as yours that say the higher ratio gears actually help the 4.7 achieve better mpg. I am not knocking the results, but in light of the math, if the engine turns over more often it usually uses more fuel. Having said that, I have noticed minimal change in the mpg between 55 mpg and 70 mpg with the cruise control on. Even holding at 80 mph the mileage doesn't suffer much --- and I get smiles-per-gallon to boot!!!
Oh, and Shorty, I run strictly 87 octane gas. Tried premium ( it's against DC recommendations ) and got worse mpg.
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shorty
Dodge Dakota
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1/27/2006
00:07:53
| RE: bad gas milage and k&n filters
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Hey choochoo, thanks for the tips I have never ran cheap gas in any vehicle and I will never use expensive gas for the same reasons plus either kind has given me a ping in my engine in other vehicles so I experimented and found 87 is the best around. plus that's what my owners manual and my mechanic recommended for this truck
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Kowalski
GenIII
1/27/2006
15:13:31
| RE: bad gas milage and k&n filters
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choochoo - close ratio is generally used to refer to transmission gear spacing, not rear ends. You mean higher or highway gearing; while the higher numerical gears are called lower gearing.
Lead, follow, or get out of the way
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