Flash the ECU?
 

Should I flash the ecu since I changed the mufflers and catalytic converter?

Which engine do you have? How many miles? Which chip? What type of power increase is promised?

Do you mean reset? Flashing requires the latest software.

The audi dealership recommended that I flash the ecu since I changed the cat and mufflers. I'm still getting the code p0430 after I put new cats on. Also after doing a search I read that there is a TSB for low efficiency bellow threshold. I have a 2001 a6 4.2. Is their a way to print out this TSB to take to audi. Read that it came out in 2005. Same year I got the car.

The TSBs are available if you subscribe at Bentley's website.

Now it makes sense. I didn't know that 4.2s had the same problem that 2.8s had. Anyways, I had to get mine reflashed and the dealer claimed that it was not covered under the warranty. I talked to my Audi tech buddy and he told me it all depends on the dealer. AOA does not cover reflash for cars that ran out of warranty. Anyways I believe mine was about $300. The code never came back since then.

Went to audi yesterday and it turns out there is no update for the 4.2. The aftermarket cats I got don't work with my car and I can't find anything else. The service manager said normally they would be 2500 for both cats together. He would give me his employee discount and they would cost 1600 together. I have no choice at this point.

Bummer... Well $1600 for both cats are really good price. If you have to deal with emission check, then there is no other way around it.

You have to be very careful before you "save" money on after market parts for these cars. We all live and learn.