.....something about "catalyst efficiency below threshold - bank 1". Any ideas what this might be or what I should do about it?

My guess is that the Techron concentrate I put in the fuel tank two nights ago fouled up the O2 sensor. I think I am going to go ahead and just reset the ECU for now and see if it comes back.

 

before anyone tells you otherwise:

http://forums.maxima.org/showthread....ighlight=p0420

look at the second post on that thread

 

Ya, went and read the TSB. Don't really feel like taking it to a dealer down here in DFW though. I will drive it back to Norman on Saturday as is and after resetting the ECU, will have to see if the code comes back......it's running just fine. Thanks for the help -- stupid emissions system on this 2001.

 

OK, so I am feelin a bit better now after reading several previous threads on this code. I will go ahead and plug the battery back in and if the light comes on, I will just take it to the dealer with TSB in hand and tell them to fix it under the 8yr/80k mile emissions warranty. The car is runnin fine so I have a hard time believing it needs anything other than the ECU reprogramming.

Here's a question though. If I take it to Nissan, will they tell me to take a walk since I have an aftermarket intake? I still have the old one, but would hate to have to swap.

 

I don't think the intake should be a problem. The code most likely will come back.