AudiGrrl32

99 A4 Avant 2.8 throwing codes, won't pass MA inspection. It's out of control loud, which has gotten progressively worse. I noticed today the flex part of the pipe is loose from the cat.

Not one mechanic will allow me to purchase cats online for them to put on. They all say that they run the risk of frying the ECM- what's the truth behind this? How do I (with assistance) put on new cats without frying the computer?

I'm not driving her right now, as it's illegal to drive in MA with loud cars and I'm concerned about trashing the car. I plan to quick fix by sealing the breaks/holes while I find an economically feasible solution. (I'm a college student but I do have some ability to fix my car as well as a few friends who are also into the eccentricities of German Engineering).

Any and all advice is appreciated.

GTA_Driver

Are you throwing codes for the cats? post your codes.

Why not just replace both flex joints in the exhaust?

By the way, if you are throwing codes for cats, it's your pre-cat, not the cat you see under the car (that's your secodary cat, which doesn't throw any codes because it is not monitored). A major job as it requires the removal of the downpipe, cutting and welding new cats.

AudiGrrl32

Codes: Generics- P0300, P0301, P0306,Specific- P1300

It does stumble, or rather, it feels as though it revs up on it's own. I' ve been having fuel gauge issues as well, which were not resolved after I replaced the purge valve.

My concern is that sure, I can replace the joints, but in Massachusetts, they are real sticklers about the codes- they essentially force us to replace the cats and we can't use aftermarkets.

I have not changed the spark plugs, but the most pressing is fixing the pipe due to the fact that it grumbles!

GTA_Driver

Those are misfiring codes. Not related to the cats.

If your fuel level gauge is acting up it's your fuel sender unit inside the tank.

Could be that your fuel pump is failing.

Who on earth suggested to replace cats? Wow.

AudiGrrl32

Someone who wants to make money. Thus, I'm asking questions rather than getting screwed. I am concerned though as the CEL flashes like crazy when I drive. I don't know- I think I'm more frustrated than anything. Fuel pump.. AHHH!

Nice wagon in the pic! She's cute!

69gaugeman

Yup, just trying to screw you. The CEL flashes as it is a condition that can damage the cats (misfires throwing extra fuel into the cats)

Take it to a muffler shop and they should be able to just change the flex pipe. It is a common failure point. The last ones I purchased were around 35$ each and less than 100$ to install.

redmond1501

If you live in Boston, and decide to replace the flex pipes instead of the whole cats, it's going to be about $250 per side to get the flex pipes replaced.

Meineke on Mass. Ave in Arlington (bus stop to Harvard Sq. is out front) will do it and they have 20% off coupons online.

Make sure whatever shop does it actually WELDS the seams. To my surprise, two out of three muffler shops I went to don't weld! They use muffler cement.

I had to replace both of mine because a drunk driver rear ended me pretty hard.

redmond1501

Also, you can use aftermarket cats in MA. I wouldn't though. Force5 auto in Concord NH has good prices on recycled OEM parts.

redmond1501

The misfiring sounds like a fuel delivery issue or a vacuum leak or both. I doubt it's an ignition issue unless the plugs have never been changed. Coil packs on the 2.8 don't fail, typically.

You can fix the vacuum issue with $20 worth of vacuum tube from the dealer. ECS tuning has aftermarket fuel pumps for $75.

AudiGrrl32

I did find a friend with a welder- as in, I WELDED it! Woo-hoo! I'll post pics- I'm super proud of myself.

However, during a spark plug change (I just bought the car last year), I noticed there was an ungodly amount of engine oil all over the socket when I was pulling out the plugs. One and two were gross. Three was fine. I chose to not mess with it any further. Not to mention, the ends of plug one were fried- gone.

I'm guessing I should replace the valve cover gaskets? How straight forward is it? I haven't looked fully at the Haynes manual yet. Any extra info not included that is helpful? I'm not driving her until I get this solved. (Needless to say, I bought the car and on day 32 (two days after the "warranty"), CEL came on and I've been slowly taking car of her quirks. ).

Vacuum issue- sounds straightforward too. Thanks!