fuel mileage

This is all new to me so I hope i do it right.  My mileage on my car seems to be getting worse and worse. I get the oil changed every 3000 mies and Dont seem to have any other problems. Does anyone have any ideas to what it could be. or what to look for, my local guy who does my oil is not a audi guy so I dont think he would know what to look for.

Pop your airbox open and make sure the air filter is in good shape. And I would think about changing the MAF sensor and fuel filter.

That's what i'm planning on doing pretty soon, because i've been getting like 20/24 lately rather than the 21/29 claimed on the window sticker. It should help to some degree.

Anyone else notice a difference in performance or mileage after replacing them?

hey guys i need help too because when i fill up with premium gas the computer says im getting 25-30 mpg but ounce i hit the halfway tank it drops and says im only getting 5-10 mpg no matter how slow i drive i think i have something wrong but dont no where to look????

cmon guys help us outt

Same thing here. I'll get about 150 miles the first half tank, then only 100 miles to empty. I've learned not to trust the gauge.

do you think it could be o2 sensors sparks or filters cause if soo ima get a tune up...?

Your first step should be to get your fuel filter changed. It is the cheapest way to start and costs only 80 bucks at dealership. If problem stays, then its either your MAF sensor or your precat oxygen sensors. I am assuming none of you have vag-com to get fault codes? Hope this helps
 

well sine i got the car the light only came on ounce and had it cleared and hasnt came on since i believe it was a misfire.....and if you have the dealer do the oil filter how much will they charge $80 or is that just for the part?

new air filter, spark plugs, seafoam, fuel filter, clean your maf. if your still getting bad mileage after that change the o2 sensor

i just ordered a cold air but havnt istalled it yet but should i get a k and n air filter also.....plus i seafoamed my car last week but only put a can in the gas tank and i know people put it in their oil and vac lines but is it necessary?

it helps. its spreads the seafoam throughout the whole engine. you should jus do it 50 miles before your next oil change. and make sure the k&n filter you get is non-oiled

do you oil it yourself or put it in your car non oiled?

get a non-oiled one and never oil it. the oil will ruin your MAF

ok sounds good but does anyone know the price for an inspection at the dealership?

Thanks for all the help I'll see what the mechanic says

First of all, the "high mileage" on the first half a tank, and poor mileage on the last half a tank is your fuel guage sender unit.  Most cars are non linear and this is common.  Calculate your mileage over an entire tank, or use the mileage calculator on the console.

Bad mileage is caused by a number of things.

Mileage goes down in winter.
Mileage goes down if you use gas that is 10% ethanol
Mileage goes down if you haven't given your car a tune up (dirty air filter, spark plugs).

Mileage goes down if your injectors are dirty Try some techron or Redline injector cleaner.

Check for codes.  Check the precat oxygen senor.

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ORIGINAL: Got2Speed

well sine i got the car the light only came on ounce and had it cleared and hasnt came on since i believe it was a misfire.....and if you have the dealer do the oil filter how much will they charge $80 or is that just for the part?

 
its 80 bucks for everything. If you know anyone who has a vag-com, you can probably ask them to scan for codes. Its much easier to diagnose it that way. But if you dont, then do all the stuff chaos said. I have bad milage in my car, but it did improve alot after i got new fuel filter. However in my case, i know that i probably have a bad maf or o2. Just to lazy to get it fixed right now

aiight thanks alot guys appreciate it