angel_o_death

hey guys, i have had my 97 12valve for about three weeks now. i love the car and have already put cold air intake, sport springs and a short shift kit on it. but i have noticed really bad gas mileage. i just filled this thing up with 76 preimium all the way and im at half a talk exactly now and i have only gone 94.7 miles on the gauge. whats up with this? am i doomed to get 200 miles to a tank? is my car messed up? keep in mind that i dont drive super easy on it, but i dont rev the thing out very often. i drive it a bit more aggressively then normal. nothing should justify this mileage... thanks

MM120

That's weird, I get over 200 miles on a half tank

angel_o_death

thanks for the post but im burning money like zigzags here.

moribundman

O2 sensors and MAF might make the engine run rich. Check the tailpipe for greasy soot. Also, try another gas station. Who knows what they sold you.

MM120

hmmmm. Do you have the generic O2 sensor numbers by chance? I forgot where I saw it. Is it more important to change the front 2 or the aft 2 sensors?

MM120

I'm sure you are.

angel_o_death

its going into the shop for a new clutch on thursday, i guess ill have the O2 sensors replaced too..

moribundman

The pre-cat sensors are influencing the air-fuel mix, the post cats sensors monitor the oxygen content in the exhaust. I suppose the latter will trigger a CEL if you blow too much crap out the rear. Oh, I should rephrase that... :-P

Those are the part numbers I have:

- Audi # 078 906 265 D
- Bosch # 0 258 003 524

MM120

There's 4 of them, & the reccommended replacement ones are about $150/each. You can do it yourself by buying the generic Bosch sensors, & splicing the firewall plug to them. They're about $50-$60 each. So obviously, you can save a lot of $$$ w/ the generic ones.

MM120

:-P