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Old 02-17-2008, 02:56 PM
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Unhappy 14.5 mpg

i have been down to 14.5 mpg recently on the 8. its a 2004 with 68k on it. in 2005 i put a cold air intake on it. but still, 14 mpg is terrible. is there any quick fixes anyone has.

also, it has been stalling more and more when coming to a stop, probably tied to the cold air intake. should i take off the k&n fiter, clean that? didnt think that was supposed to be cleaned, but not sure. or is there another fix for that?
Old 02-17-2008, 03:02 PM
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I get 12.5mpg on avg so cry me a river.. lol.. I wish I got 14.5mpg. If you think your air intake is the problem I'd sugest taking it out and see if your theory is correct.
Old 02-17-2008, 03:04 PM
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go to K and N's web site, there is a cleaning schedule for that filter.. and it's not "never"
Old 02-17-2008, 03:16 PM
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clean air filter
clean the maf
change the spark plugs /coils maybe also
check tyre pressures
check cat is clear
start premixing
Old 02-17-2008, 03:26 PM
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Man, if I got 15.5 mpg on my FD, I'd probably start crying with joy. I'm somewhere around 10, premium.
Old 02-17-2008, 03:55 PM
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is it k&n v1 or v2?

Idle issues are known with 1. I would also recommend an engine compression test if your idle doesnt improve after you check the standard maf, spark, coils, etc.

Poor idle can sometimes be serious.
Old 02-17-2008, 03:58 PM
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i just got 15.15 mpg on my last tank. i red lined it a lot so....you must be doing the same. just drive like a granny for 1 tank and see if you get an improvement.

last tank = 203 miles $42 for fill up 13.396 gallons used
Old 02-17-2008, 05:09 PM
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Originally Posted by gfschoone
i have been down to 14.5 mpg recently on the 8. its a 2004 with 68k on it. in 2005 i put a cold air intake on it. but still, 14 mpg is terrible. is there any quick fixes anyone has.

also, it has been stalling more and more when coming to a stop, probably tied to the cold air intake. should i take off the k&n fiter, clean that? didnt think that was supposed to be cleaned, but not sure. or is there another fix for that?
K&N version 1 is worthless. (big filter)
K&N version 2 is better (carbon fiber tube with filter in middle.) -
If it doesn't look like the filter above, then thats whats causing the stalling.

Otherwise you probably need to change your sparkplugs or your ignition coils.
Old 02-17-2008, 06:09 PM
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I've been averaging 15mpg as of late, so it sounds almost normal. My mileage was unaffected by installing a MS CAI, and it really doesn't vary much by driving conditions or style (14-18).

Last edited by Jasonawojo; 02-17-2008 at 06:14 PM.
Old 02-17-2008, 06:12 PM
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I get 15-16 mpg, both when I was NA and when I'm turbo.

If I baby it I can hit around 19. But that really never happens.
Old 02-17-2008, 06:17 PM
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Just drive like a granny and prevent the second set of fuel injectors from activating.
Old 02-17-2008, 06:27 PM
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23 on the highway, around 17 in the city.

Consistent 270 to 280 miles per tank (about 13 gallons).

2005 6MT.
Old 02-17-2008, 06:33 PM
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17~20 for me. 2004 54,000 totally stock.
Old 02-17-2008, 06:34 PM
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Originally Posted by RotoRocket
23 on the highway, around 17 in the city.

Consistent 270 to 280 miles per tank (about 13 gallons).

2005 6MT.
i reckon you premix, yes? :D

al
Old 02-17-2008, 06:37 PM
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Originally Posted by alz0rz
i reckon you premix, yes? :D

al
Never.

I use 89 grade and either Havoline 5W-30 (in the summer) or Havoline 5W-20 (in the winter).

About 40% highway driving, and 60% city.

Edit - had my seasons mixed up.

Last edited by RotoRocket; 02-17-2008 at 06:48 PM.
Old 02-17-2008, 06:43 PM
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come on, one post, then leaves,,,,,,,,,,,,,,,,,, troll.
Old 02-17-2008, 08:36 PM
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It's due to winter gas and you keeping it a high RPMs
Old 02-17-2008, 10:07 PM
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i get about 14-15. dont complain
Old 02-17-2008, 10:11 PM
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Razz is probably right - winter gas will be around 10% less mileage.

I was really surprised when I bought the ScanGauge (it reads out fuel consumption) that the high revs were such a penalty - at constant speed, twice the revs equalled twice the fuel use. I was expecting a penalty, but didn't expect such a hit.


S
Old 02-17-2008, 10:23 PM
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Originally Posted by StealthTL
Razz is probably right - winter gas will be around 10% less mileage.
I was really surprised when I bought the ScanGauge (it reads out fuel consumption) that the high revs were such a penalty - at constant speed, twice the revs equalled twice the fuel use. I was expecting a penalty, but didn't expect such a hit.
S
That's when overdrive gearing shines.
Old 02-17-2008, 10:23 PM
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Originally Posted by Brettus
clean air filter
clean the maf
change the spark plugs /coils maybe also
check tyre pressures
check cat is clear
start premixing
^^^^^^

x2

and to the op.

where are you? have you maintained the car at all?

beers
Old 02-17-2008, 10:24 PM
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Originally Posted by StealthTL
Razz is probably right - winter gas will be around 10% less mileage.

I was really surprised when I bought the ScanGauge (it reads out fuel consumption) that the high revs were such a penalty - at constant speed, twice the revs equalled twice the fuel use. I was expecting a penalty, but didn't expect such a hit.


S

Yep. Doing higher speeds even in completely clear traffic on the highway sucks gas quickly in the 8.

So, whether you're short shifting in city driving, or driving at faster speeds on the highway, you will pay a definite penalty in mpg.

In my experience, 65 to 70 mph, with obviously clear freeways, yields around 22.6 mpg for me.
Old 02-18-2008, 11:52 AM
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Originally Posted by RotoRocket
23 on the highway, around 17 in the city.

Consistent 270 to 280 miles per tank (about 13 gallons).

2005 6MT.
That's better than the mileage of a tank I get in my RX-7, and those things are 16 gallon tanks
Old 02-18-2008, 12:37 PM
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Originally Posted by Renesis SE3P
Just drive like a granny and prevent the second set of fuel injectors from activating.
Is this true that driving more "slow and controlled" if i put it that way, stops other injectors firing and should help MPG?
Old 02-18-2008, 12:42 PM
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I havent figured it in abotu a month but i was getting close to 20 for a while


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