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I'm trying to think of reasons why the Mystique has been getting VERY bad gas milage lately. It hasn't been making the "moosing" sound though. I just changed the plugs and cleaned out the UIM/LIM. Any ideas?
I'm sure the winter gas mix and cold weather hasn't helped but it seems worse than it should be. We had just shy of 200 miles and a little under 1/4 tank of gas left (yes it was filled up completely).
Could the IAC be partially stuck? It isn't moosing....
Aside from the bad gas milage it runs fine. No problems whatsoever, aside from the gas milage.
1999 Mystique LS V6
Alpine CDA-9807, Rear deck sub, Opt. TB, K&N RU-3530/MAF adaptor, custom heatshield, FSVT 17's, SCT 4-program chip, Eibach's/ST200's, Hella Fogs...
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o2 sensor,tire presure, fuel,and air filter, even if you dont have a checkengine light on changeing the o2 sensors can make a big difference,
98 svt sil/blu 3.0 oval heads full P&P, msds headers,bat kit,2,1/2exhaust 30 inch glasspack and 2 spintech mufflers 14.78@94mph
with my mechanical arm i can shift gears in less then a twentieth of a second for sale $7000
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Tire pressure is at 42PSI all the way around (max is 44 according to tires). Fuel and Air filters weren't changed very long ago(10k miles or so).
o2 sensors on the other hand have never been changed... that could be good to check out... Thanks!
1999 Mystique LS V6
Alpine CDA-9807, Rear deck sub, Opt. TB, K&N RU-3530/MAF adaptor, custom heatshield, FSVT 17's, SCT 4-program chip, Eibach's/ST200's, Hella Fogs...
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Joined: Sep 2003
Posts: 713
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98 svt sil/blu 3.0 oval heads full P&P, msds headers,bat kit,2,1/2exhaust 30 inch glasspack and 2 spintech mufflers 14.78@94mph
with my mechanical arm i can shift gears in less then a twentieth of a second for sale $7000
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Joined: May 2000
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If you change the O2's, just replace the uppers as the do all the calibrations that count  This is why I always check my MPG, just to see what its doing  BTW, is your O/D working correctly? The reason I ask is because if its stuck in regular DRIVE, your mileage will suffer some, especially on the freeway.
Last edited by The Striped SVT; 12/29/03 03:47 PM.
"THEE" Roger R
USMondeo@aol.com
2005 Crossfire Limited coupe'
-FOR SALE @buyout price & I'll...
-throw in my 93' Regal as winter car
*Dragon Run 06'...Oct 12-15th*
Puur-fection Auto Detailing
Complete packages from $140.00
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I've been getting crappy mileage from day one. Bought it in Georgia & drove down to Florida. The first tank of gas 33 mph. Next tank it dropped to 27, now 23 mpg every day in mixed driving.
I visited the hills of Tennessee in October for some HARD driving & my mileage jumped to an average of 28 mpg. Over 32 mpg on the first leg on the way back.
I think it has more to do with the gas than anything else. I may change my O2s some day - just to see if there's a difference, but for now I'll just pay N pay N pay for the extra fuel.
Must be that jumbly-wumbly thing happening again.
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Yea I've noticed the Duratec does like to get abused. I get the same gas milage beating the living snot out of my Contour as I did when I drove it normally. My 6 is getting about 23 for mixed, now it has 1400 miles on it. Yes 1400
Mazda 6S, V6, Speed Yellow
5 Speed, Sport package
Bose audio
Painted 'stash and HIDs!
w/Injen 1/4 14.750 @ 94.94
Former car:
99 Contour SE Sport Black MTX V6
SVT plastic...
1/4 - 15.012 @ 90.58 
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Originally posted by mmarfan:
Yea I've noticed the Duratec does like to get abused. I get the same gas milage beating the living snot out of my Contour as I did when I drove it normally. My 6 is getting about 23 for mixed, now it has 1400 miles on it. Yes 1400
Yea they do... we got 29 on a trip to the cottage last summer... I drove it pretty hard too... 
It does go into overdrive, tranny is working fine.
1999 Mystique LS V6
Alpine CDA-9807, Rear deck sub, Opt. TB, K&N RU-3530/MAF adaptor, custom heatshield, FSVT 17's, SCT 4-program chip, Eibach's/ST200's, Hella Fogs...
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Is the temp gauge coming up to normal or is it staying low?
If the engine is always running cold, you will get crummy gas milage because the processor will think that the engine isn't warmed up yet and stay in "choke" mode.
Jim Johnson
98 SVT
03 Escape Limited
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Yea, it comes up to normal...
1999 Mystique LS V6
Alpine CDA-9807, Rear deck sub, Opt. TB, K&N RU-3530/MAF adaptor, custom heatshield, FSVT 17's, SCT 4-program chip, Eibach's/ST200's, Hella Fogs...
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