Well if you remember from my last thread, getting the BMW didn't workout, but now, of course, I got a few problems with my lovely A6.

several months ago I got a check engine light. I checked the codes and they were for cylinder misfire and some sort of (air filter -- don't really remember though).

I read some reviews online and they said the first step to do is deleting the check engine & seeing if it comes back. So I deleted it, and it never came back. I also didn't feel that there was anything wrong with the car's behavior. I thought the car was fine.

About a week ago I got another check engine, and this time it was two codes for the oxygen sensor. Online it says that this is usually due to an older misfire or that (air filter- or whatever it was). I did the same thing: Deleted the check engine light, and it never came back.

Is something really wrong with the car, and if there is, why does the check engine light never come back. Shouldn't it come back even if I deleted it a 100 times.

Car doesn't act any different, but I'm not sure if the car is just collapsing without telling me.

 

If it ain't broke don't fix it... as long as you keep up with the maintenance that is.

 

Could be "intermittent " problem, that's why it doesn't come back right away after deleting the fault code. The O2 sensors are known to go, need replacing, they don't last forever. Find out which one, I think you may have 4 of them, 2 in each pipe, before and after the Cat.

 

Your Audi must punish you for attempting to ditch it. Your car has feelings to you know. Maybe it is telling you that it doesn't like you either.

 

Jeffla is absolutly correct! LOL


We don't know how old your A6 is but what your describibg is common as an Audi ages. Some CEL's are designed to come on after a few times and others come on immediatly. Random misfire CEL could be leading to something a bit more serious, so you need to write down the causes and see if there is a pattern. Other wise just reset --reset -- reset -- and have fun..

 

yeah I guess Jeffla is right too;

The misfire code came once about 6 month ago and never again, the o2 sensors code appeared about 3 weeks ago, and didn't come back yet. I'll see what happens.

I also remember that I was checking for codes while the car was on, but not actually running. I found some of the old codes when I did that, so I reset them, and again, they never reappeared.

My car is a 2000 2.8Q 120000miles


EDIT: OH ANOTHER QUESTION: IF IT'S TRUE AND THERE'S SOMETHING WRONG EITHER WITH THE MISFIRES OR THE O2 SENSORS, WOULD THE CAR FEEL OR BEHAVE DIFFERENT IN ANY WAY?

 

I am not a mechanic and cannot answer to the "misfiring" - could be an injector going bad, could be that a spark plug has a wider gap (unless are the type that don't require gaping), could be that you need a new spark plug wire set, could be that you need a new coil, etc

However, as far as the O2 sensors go, typically you should notice a difference in how the engine runs. Some symptoms are either sputtering (running lean) - rough idling, or running too rich - a significant decrease in gas mileage.
I am sure some people who know more will chime in, but monitoring yourself the way the car runs over a period of time could give you more clues.

 

well the check code for the cat converter/o2 sensor came back on. I really don't know much, but is there a way that I can locate the cat and clean it or something.

 

It is probably one of your O2 sensors going bad. Time to change them.

You should never attempt to clean a cat. They scratch too much....

Bob

 

Try washing them with water then...