Hi Everyone,

I searched High and Low and can not find the Pre Cat O2 Sensor with Wideband for my
2004 TT 225. I just replaced the post cat O2 sensor but I was told that the top or Pre Cat
O2 controls the Air/Fuel mix and my car is running rich so I thought I would replace to O2 which
should be done anyhow after 60k+ miles.
Any help or Part Numbers would be greatly appreciated.

Thanks in advance for your help!

Tom in INdy
04 TT 225

 

how rich is it running.........if its chipped its better to be running rich than lean !!! thats how you end up with detonation. not a good thing !!!

 

rich + no code usually = vac leak somewhere.

 

I have the scangauge II and it reads -13 which is rich. + would be lean. It should read between +5 to -5. I am running a 4bar fpr which the Revo Stage 2 calles for. I am also running a 42DD DP, Modshack **** and Boostmachine. I switched back to the original OEM MAF housing but that made things worse and I was running a - 23 rich. I did swap out the lower (Post Cat) O2 Sensor but that didn't really change anything. So I am thinking it might be the Pre Cat O2 sensor since it is a wideband O2 sensor and controls Air/Fuel mixture.
The car runs great otherwise.But it does occasionally blow black smoke out the exhaust when Ifull throttle accellerate.
Cincy,thanks for your input. I have checked all the hoses that I could find and I don'tsee or rather hear any vaccum leak.But I realize they are hard to find.
Thanks for your help!

Don't pay attention to the signature. I know have a 2004 TT 225 which is different somewhat from the 01. Especially in the O2 sensor department.

 

unless you know what those -5 +5 really mean vs eg 12:1, that info is pretty much a waste.