Ok, I have codes P0304,5,6 with rough idle but seems really smooth over 1000rpm. I am guessing it is the cam tensioned because I would think that if the timing had jumped that it would be rough at speed too;Is this accurate?. Or, is it possible that it would smooth out at rpm?

I have changed all the vac-lines , except the one that runs down to the vacuum res. I have changed the main breather hose. new plugs on 4, 5, and 6.

Thanks.

 

Bump

 

Did you do any timing belt related work recently?

 

Not nearly enough info to assess.

 

Ya like what motor? -- what year?

 

Would a timing belt that is off one tooth only vibrate (be noticeable) at low rpms; any year, or any motor that can jump a tooth? Would a defective cam tenssioner cause misfires at only low rpms (under 1000); Any year, any motor that has them ( or a 2001 A6 2.8l if you think that would make a diff, but I do not see why as their function is the same on all models that have both, but I could be wrong)? Just assume everything else is not the problem and those are your two choices that could be the cause and you are trying to decide which to go after first to save you 4 to 6 hours work. So a recap, you have missfires at under 1000rpm for sure, and at speed you feel nothing. You are confident that it is the cam tensioner or jumped a tooth, which would cause those systems, or both. Again, I just figured that if it was a jumped tooth that it would vibrate at speed as well as at low rpms as it would be out of time no mater the rpms, where as if it is just the tensioner, it could be out of time at low rpms, but at speed it could be in time. That is my assumption that I am not sure about and would like confirmation of.... I apologize if my level of knowledge just makes those two question and my reason for asking them seem straight froward when they are not.

Thanks again for your time.

 

Sorry, about a year ago.

 

So you are just getting 4,5,6? Also did you change the plugs before th codes or the after the code? BTW, what motor do you have?

 

Year is in the post (2001 2.8) (but is not relevant to the questions) I once again ask that all other possible causes not be considered; I am seeking an answer to the very specific questions that I asked. Thank you.

 

Sorry I did not read the 2.8 part. The reason that I ask was 2.7T has ignition control modules that affects each bank. If one goes bad, then it is possible to get your symptom.

So based on what you are telling me... It is possible for the timing belt to jump a tooth. If that is the case, then you probably have a failing tensioner.

As for the cam chain tensioner, I doubt that is bad unless you are really hearing a loud chatter. If you want to make sure, then just pop the valve cover and visually inspect the pad. You can do that in a couple of hours with a set of valve cover gaskets.