Real bad MPGs in my 2010 A4 Avant APR Stage 2 - Please Help!

[Bongerong]

I recently purchased what I consider a very well put together A4 avant with an APR Stg2 tune, Goodspeed DP, full Goodspeed exhaust, Carbonio intake, 034 hose, Goodspeed intercooler and I'C pipe, plus some other go fast bits and pieces I'm forgetting. I love the car and over a stocker B8 2.0 it hauls. Trouble is I have noticed that my MPGs are pretty god awful, 13-16 MPGs awful. I have also noticed a strong (read: rich) exhaust smell when sitting idling in the garage and at the light (this could just be the Stg 2 tune and exhaust setup).

I drive in the city with some stop and go and don't really romp on the throttle that often. The car has 29k miles and runs fantastic but this gas mileage makes me cringe a little. I should add that I drove the car in the Malibu canyons two weekends ago and and had it good and hot, then when under pretty hard acceleration I noticed the car sputtered when I gave it throttle. It felt like a hesitation in the throttle (maybe fuel cutoff or something). It only did this for a short while and I haven't noticed it since (of course as soon as it happened I cooled the car down some and took it easier). When I first started cooling the car I noticed the turbo was red hot and that there was some other steam/smoke coming from what looked like the injector area. This may have been nothing and had no contribution to my current problem but it couldn't hurt to add it in for background. Note: I am having the DP and turbo coated in the future to help with heat soak.

So driving around town the computer tells me anywhere from 13-16 MPGs and sometimes when it sits idling I can see that number actually drop even more. I filled up the other day and it took 1/4 of a tank to go basically 35 miles in the city. No codes have been thrown and I don't have a VAG cable yet to hook up for other scanning. I plan on checking the obvious suspects since doing my initial research on here: PCV, plugs, exhaust leak, MAF, fuel filter, air filter. With my mods not sure I should take it to the dealer for this as they might void the warranty. And may end up heading down to Eurocode tuning or RavenMS next week for a helping hand. But I was curious if anyone had any thoughts on this issue? Feedback is appreciated. Thanks and let me know if I can add anything else.

[PDong]

A couple of pieces of advice.

First off, I recommend posting this in the technical section.

Then, maybe, over on Audizine. It's a much more active board than the B8 here. (sorry George, et al)

I had some hesitation jutters a year ago. It was bad in the heat, and it was really strange, 1/2 to WOT when the revs got between 2000-2500 rpm.

I added some SeaFoam to the oil and gas and haven't had an issue since. Weirdly, I've also varied my fuel choices, started getting Kroger fuel, as they just installed the tanks at a completely new station. Not sure it had much to do with it, but I feel like the SeaFoam was a real help.

Good luck.

[PDong]

See you already did put it on AZ!