OK... It cost me a bundle ($872), but I finally have my A6 running clean and ready for my second crack at the MA state inspection. I failed it a couple of months ago due to emissions issues, CEL, & associated codes.

The bill breaks down as follows (accumulated over two different visits to my mechanic): $391 for a new 02 sensor to be installed + $481 for labor to replace the Air Intake Temperature sensor wiring harness. The 02 sensor died (not an uncommon problem here) and the wiring harness for the IAT sensor was chewed on my some rodents who must have gotten out of the cold this winter courtesy of my warm engine. Because the intake manifold needed to be removed, it ended up requiring six hours of labor (thus the rather large bill). While he was in there, I had him put in place a Samco Throttle Body Boot and F-hose (a little preventative maintenance from boost leaks).

My wallet is hurting but I'm happy to have my stead running well again.

In the interest of providing good forum content for people to search on these issues, here are a couple of links to my previous posts on this issue:

- The first one.
- The follow-up.

Thanks to all for your help & suggestions.

MODS/UPGRADES:
17x8" BBS RKs (great AW story about how I got them...) | H-sport anti-sway bars | ToyGuy short shifter |
IceLink/iPod integration | Escort 8500 hardwire | fog/running light rewire | HomeLink home lighting control |
fold-down bag hooks in the trunk | aux power socket under the armrest | hidden Symphony EQ settings |
remote locking control recode | debadged

SUGGESTED READING FOR C5 A6 OWNERS:
2001 A6 info from AudiWorld | 2001 A6 info from Edmunds.com |
Audi 2001 maintenance schedule | Stoney's links (the ultimate A6 links page) |
the nOOb's guide to everything | how to make your car shine

The other ride: 1998 Mitsubishi Montero (typically with a kayak on top)