My Peake R5FCX-II tool gave me an oxygen sensor error and a lambda control error. I did the voltage tests according to the directions in Bentley. Oxygen sensor seems to be dead.

Thing is, I called the $tealer up today, and they quoted $500 NZD ($300+ USD)for the O2 sensor. I'm like whatt? It's supposed to cost about $150NZD. As such I think I'll have to postpone getting a replacement, will probably end up getting it from the USA or something. How important is it? The car is already running rich, stinks like crazy when you start her up. Fuel economy is about 8km/litre. The exhaust doesn't flow properly - I have a friend with the exact 320i but maintained by the $tealer, and his exhaust outputs a really smooth flow of air, while mine does it the put-put-put way.

Will the exhaust problem be fixed if the O2 sensor is replaced? Other than the problems I have listed, will any other problems result from a bad O2 sensor?

PS: I also took the ICV out. It was pretty clean, but I cleaned it with carb cleaner anyway. Tested it using Bentley method and it's in good condition so that isn't the problem.

It's around 100 bucks on bimmerparts, get it asap. You'l save on gass for one and it'l pay itself soon.

Thanks :) Anyone else with opinions?

yea, very important - not sure if it will solve your odd exhaust output, but it will probably run like shite and possibly kill your cats if you don't get it fixed ASAP! I'd call Bimmerparts.com and see how much it would be to air-freight you one. I'm sure it will still be way cheaper than the dealer I would think!

check the specials section on bimmerparts.com. they had them for like $80 awhile back!

Thanks man, I think I've found a source for it for a really good price, so hopefully I'll be getting a new one next week!