What to check for poor MPG?

[Agro]

Car drives perfectly, but even if I baby it the entire tank (mostly freeway to/from work), never shifting above 3k rpm, and doing a lot of 1st 3rd 5th, I get at most 23mpg. Others out there have said they can get 30mpg.

2004.5 Audi A4 B6 1.8T FWD USP, APR K04, FMIC, Forge DV, Test Pipe, K&NAir Filter, you get the idea...

I know my secondary air injector pump isn't working well as it whines every time I start the car, but my understanding is that is just to help warm the catalytic converter up so it helps with emissions (I don't even have a cat).

So i am thinking of taking my car to GROUP 5 Motorsports. I want to change my maps from 91 (chipped) and 100 (race) to 91 (bone stock) and 91 (chipped). I also want to have them replace the secondary air pump as i am tired of the noise. Before I take it to them, I will once again clean my K&N, replace the fuel pump, replace my plugs, clean/lube the DV. If my MPG still blows, what else would you recommend I have them check?

[Auditude2.0T]

you do have a lot of mods that could affect your mpg.

[drexplode]

spark plugs, fuel filter, air filter, tire pressure, oxygen sensors, oil, gas quality, wheel bearings, brake pads that are dragging

thats all i can think of at the moment.

[Groove1797]

check valve.... I have the exact same mods as you and I still get 350 -400 a tank. My check valve broke and I was getting 300 max for a little

[DELUX]

I think with the presence of shitty west-coast gasoline, I think 23mpg sounds just about right for an average mpg. I average 25mpg with similar mods and on long highway trips i get about 26.5mpg, but I also use super high quality shell & bp 93 octane fuel.

[Groove1797]

Explain how the 91 in CO is any different from CA's?

[DELUX]

Explain how the 91 in CO is any different from CA's?

I dunno if it is. 91 is just shitty in general

[Agro]

check valve.... I have the exact same mods as you and I still get 350 -400 a tank. My check valve broke and I was getting 300 max for a little

My best tank was like 430? While that might sound nice, it isn't that great, since I have an 18.5 gallon tank.

I will make note of all these things and then when i take it in, have them check them out.

[Agro]

spark plugs, fuel filter, air filter, tire pressure, oxygen sensors, oil, gas quality, wheel bearings, brake pads that are dragging

thats all i can think of at the moment.

I plan on changing the fuel filter soon. It's about 30K miles since the last time I changed it. The air filter is a K&N and I will need to clean it and re-oil it up with the filter-charger kit. That is such a PITA. Maybe I should go back to stock :)

I wonder about my oxygen sensors though and maybe my MAF sensor? I have no way to know if those are working properly. I have brand new pads in my garage that I am going to have the shop install too, since I am about 35k miles on these pads (amazing).

[Groove1797]

My best tank was like 430? While that might sound nice, it isn't that great, since I have an 18.5 gallon tank.

I will make note of all these things and then when i take it in, have them check them out.

Are you an avant? Because a sedan's tank is 16.5

[AudiA4Turbo22]

i get 330 mi to a tank max driving real careful ur still good man!

[Elliott]

Are you an avant? Because a sedan's tank is 16.5

Pretty sure its 17gal.

[Agro]

Are you an avant? Because a sedan's tank is 16.5

FWD sedan. The FWD has a larger tank.
Don't ask me how, but I've gotten 19 gallons in my car on a couple of occasions. Sure, I was on fumes, but still its 18.5 gallon tank, I can get more in it.

[Elliott]

check valve.... I have the exact same mods as you and I still get 350 -400 a tank. My check valve broke and I was getting 300 max for a little

Which check valve? Aren't there a few?

[drexplode]

I plan on changing the fuel filter soon. It's about 30K miles since the last time I changed it. The air filter is a K&N and I will need to clean it and re-oil it up with the filter-charger kit. That is such a PITA. Maybe I should go back to stock :)

I wonder about my oxygen sensors though and maybe my MAF sensor? I have no way to know if those are working properly. I have brand new pads in my garage that I am going to have the shop install too, since I am about 35k miles on these pads (amazing).

That is the other thing i forgot...MAF sensor.

Pick-up some CRC MAF cleaner and spray the sensor a few times. Make sure it is dry before re-installing and operating the vehicle.

[scorneil]

check for boost leak - that can affect your mpg as well

[rudtf]

damm i don't even have a k04 and just tested my mpg's and i'm getting 22. I thought that was normal with my bigger injectors and what not. hmmmmmmm