Dont get test pipes you'll regret it. sounds terrible rasp is to annoying just go with hfc a little more but worth it. I had test pipes, never got a tune and no cel ever came up. I'm currently waiting on some Kinetix HFC right now.

 

Check under the hood and see if you find a large snail shaped metal object with piping running to your intake... I found a couple of these under my hood and they caused very a similar MPG loss

lol lol lol

But seriously, if you're getting 8mph NA there's something very wrong, like the others said.

 

If you run your car @ WOT 100% of the time, you will get 6-8 MPG. For you to be getting anything around 8mpg (if that is an accurate number) you clearly are having an issue somewhere.

You should know how many miles you normally get on a fuel tank. For instance, I know by the time my gauge reads half tank I am normally at 150 miles. 1/2 tank is normally around 7.5 gallons for me. I average around 20mpg in the city.


With this being the current topic - there is evidence to suggest that using test pipes w/ non foulers can cause a dramatic fuel consumption increase. As per the FSM, the car will use the rear O2 sensors to achieve stochiometric AF ratios during low throttle situations (ie, <50% throttle for more than 3 min). If your O2 sensors are not in the direct stream you throw off the readings. Most people w/ test pipes have issues with CEL so they use non-foulers. ART pipes come w/ 90* bung extenders.

 

Hey let me know how those Kinetix HFC's work out for you

 

running your A/C 24/7 while you're driving will kill the mileage too. When was the last time you ran a simple bottle of Fuel Injector Cleaner through the car? When was the last time you changed your oil? Tranny fluid?

 

Up dates?