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Gas mileage and engine temp questions

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  #1  
Old 04-23-2012, 05:28 PM
01quattro's Avatar
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Default Gas mileage and engine temp questions

So probably like the last week ive noticed the mpg the computer shows even less when im purposefully driving really calm and low rpms it seems to be burning more fuel then usual. Could there be anything wrong that its not throwing any codes? I already have done:

10 months ago-

K&n drop in air filter
Fuel filter
Denso iridium plugs gapped at .28 cause im chipped

Coolant change was done last august also. And my oil probably has 3700 miles on it or so. Mobil1 full syn and mobil1 filter.

Could it be that the engine is not warming enough? This is after about 10-12 min of driving. 70mph on highway for most of it and then a backroad or 2. Took this pic at a stopsign quick.

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Also my ecs light is on cause i had it turned off, i dont have check engine or anything either.

It also seems after i park it the last week, almost as if fuel is disappearing. Before after i parked it my range woukd stay the same or go up. Now its usually lower and then i drive like a grandma and it goes up a little, before the range would go up more.

Any insight?

Thanks
 

Last edited by 01quattro; 04-23-2012 at 05:38 PM.
  #2  
Old 04-23-2012, 05:35 PM
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Coolant temp usually sits in the middle of the temp guage. You could have a thermostat going bad which will make the car run richer which will have a effect on the fuel economy. Oil temp is dependent on external temp & how hard the car is driven.
 

Last edited by M5S5; 04-23-2012 at 05:37 PM.
  #3  
Old 04-23-2012, 05:39 PM
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It goes halfway if lets say i drive the car for 10-15 mins park it and start it back up again like 15 min later. Today its about 50 degrees maybe a tad more.
 
  #4  
Old 04-23-2012, 05:47 PM
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If you were driving on the highway for 10-12 at 70 mph the engine should be at operating temp allready. You might have a pending map cooling fault code stored in the ecm.
 
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Old 04-23-2012, 06:23 PM
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If i hookup my vag com i should be able to see them correct?
 
  #6  
Old 04-24-2012, 12:32 PM
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Any other insight? Im going to hookup the vag com later today after work.
 
  #7  
Old 04-24-2012, 01:53 PM
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Only thing that comes to mind is your t-stat and coolant temperature sensor a bad coolant temp sensor can make your car run rich.
 
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Old 04-24-2012, 05:26 PM
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So i hooked up the vag-com and ran a scan. No codes or anything. Could this still be an underlying issue of failing t-stat or coolant temp sensor? I dont feel like ripping half the drivers side engine bay only to find new t-stat didnt help.
 
  #9  
Old 04-24-2012, 05:31 PM
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The cheapest & easiest is to replace the coolant temp sensor (dealer only) No Autoblown Chinese crap. Also replace the o-ring & the clip.
 
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