# Fuel Mileage Dropping



## dagooaz (Jun 3, 2007)

Hi all. I have a problem with my 2007 Rabbit 2.5l. My wife drives 80 miles round trip to work, all highway. She had been getting about 27 to 27.5 mpg's until about the last 30 days when it dropped to 24. Driving habits haven't changed, nor has fuel. We buy from the same station every time and Colorado has been on winter fuel since about October. Air filter looks good, plugs were replaced about 15-20k ago. Any ideas what could be causing the sudden drop in MPG's? Any help is appreciated.


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## thygreyt (Jun 7, 2009)

how is the maintinance??


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## dagooaz (Jun 3, 2007)

Maintenance has been great since I bought it. It had 61k on it when I bought it and it now has 69k on it. I changed the oil at 67k with the proper synthetic oil, but that made no difference. Dealer sold it as a CPO and claimed all work had been done. Carfax shows records of dealer maintenance for the life of the vehicle.


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## a7xogg (Nov 25, 2008)

any engine cleaner in the maintenance schedule


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## dagooaz (Jun 3, 2007)

None of the previously performed maintenance records show engine cleaner.


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## cyclegrip (Dec 3, 2006)

Fuel filter done with oil change?


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## dagooaz (Jun 3, 2007)

I didn't do a fuel filter, but I guess I can try that next. Thanks.


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## Gunbunny08 (Nov 13, 2008)

I would do the fuel filter for sure and at least check the air filter or have it checked. I noticed a difference in my MPG a while back before I did my 40k service. Changed the air filter and fuel filter and MPG's were back to normal. It could also just be winter gas. It usually tends to burn a little faster. Not sure I know what winter means for you though. I would still change those two filters if they haven't been done in a while, or ever.


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## rob454 (Sep 18, 2009)

Colder weather will cause you to have MPG decreases.


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## magics5rip (Mar 17, 2004)

rob454 said:


> Colder weather will cause you to have MPG decreases.


QFT


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## Salty VW (Sep 2, 2004)

Here's the DIY I used when changing my fuel filter. The filter part number is different for a 2.5L, but the procedure is nearly identical. 
http://www.golfmkv.net/blog/archives/10#


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## dagooaz (Jun 3, 2007)

Thanks for the link salty! I have already ordered an air filter, it will be here on Monday. I'm going to get the fuel filter this week too. It's not the winter gas that is causing the decline in mileage. Here in Colorado, we switch to winter gas in October and the mileage starting going down in late November, early December time frame. Thanks for all the responses.


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## Unilateral Phase Detractor (Aug 23, 2005)

Low tire(s) perhaps


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## seanmcd72 (May 14, 2008)

classicjetta said:


> Low tire(s) perhaps


Yes this has affected my mpg for sure :thumbup:


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## Schagephonic (Feb 5, 2009)

I also live in CO and do see a small drop in MPGs when the weather turns cold but not 20% as you describe. I was listening to the Car Guys on NPR recently and a guy with a Ford Explorer was describing the same exact problem, a 20% drop since the fall. They strongly believed the problem was with a sluggish thermostat that was not closing all the way or was delayed in closing. So, they recommended changing the stat. G'luck


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## jsag (Nov 27, 2007)

I used to drive my 06 jetta 320 miles on a single tank, city and highway. Took the car to the dealer for the 40k and that reall about the" ignition coils", after that the most I get is like about 250 miles; that started back in the summer time and of course winter time it is even worst.


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## rob454 (Sep 18, 2009)

I get 400 miles on a tank in the summer. In the winter I get 320 miles.


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## PanzerVW (Jan 9, 2003)

I also recommend removing your MAF sensor and spraying it down with MAF cleaner- worked pretty well for my 08'


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## inspectahpete023 (Aug 30, 2008)

dagooaz said:


> Thanks for the link salty! I have already ordered an air filter, it will be here on Monday. I'm going to get the fuel filter this week too. It's not the winter gas that is causing the decline in mileage. Here in Colorado, we switch to winter gas in October and the mileage starting going down in late November, early December time frame. Thanks for all the responses.


Did you change your fuel filter yet and see any results? I'm having bad MPG problems too, but I just bought a 2007 Jetta 2.5L at 49k and now has 51k and from the start i was getting 300 before the light comes on, so that comes out to 21mpgs a tank and thats with 65% highway and 35%regular driving, it says our car gets 30 highway and 22 city, so i should be getting atleast 25-26 mpgs, so i'm just trying to figure out what it could be. Let me know if the fuel filter helped. Thanks


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## dagooaz (Jun 3, 2007)

Nope, fuel filter made no difference. The only thing that made a difference was when I did a TDI 5th gear swap. The car does 95% highway, but it's still only getting about 26 to 26.5 mpg. I'm now getting about 330 to 340 miles a tank. Hopefully it's the cold that's causing it and it gets better this summer.


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