A6 misfire

14FOREST

MEMBER
AUDI A6

I have a misfire on my Audi A6 2.7t Quattro. It started on Cyl #3 and 4. I put in some fuel injector cleaner and replaced the plugs and Cyl #3 misfire went away. I replaced the coils on Cyl #3 and #4 but it still misfires. This is a very strange misfire. It misfires at idle, off idle and under load but seems to go away at 2000 rpm with no load and 2800 with load. This all started on the same day. Could it be fuel
injectors?

5 Replies

MERLIN2021

MECHANIC
17,250 POSTS

There is a lot you are not telling us...What condirion were the plugs you removed? I'm thinking you need to do a compression test I don't see the year on this post. That said here are some testing tips,

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Sunday, September 16th, 2007 AT 2:17 PM

14FOREST

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9 POSTS

The car is a 2000. I just had the timing chain replaced, cam seals and valve cover gaskets. The mechanic checked the whole car including compression. Everything was in spec. Spark plug # 4 was fouled before I replaced it. Spark plug #3 was OK.
Half the tests you sent me don't apply as I already replaced the coils and plugs.

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Tuesday, September 18th, 2007 AT 7:33 AM

MERLIN2021

MECHANIC
17,250 POSTS

Ok so the coils have been replaced, what about the plug jackets? If compression is good, these cylinders are on oppsite banks and both at the front position, are we sure the camshaft sensor is set correctly? P.S. Just tryin to help, I am not an Audi specialist! But I did spend quite a bit of time researching for you, if you need more reseach call me! Let me know how things go. Good luck. I do like a nice ride myself.

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Tuesday, September 18th, 2007 AT 6:21 PM

14FOREST

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9 POSTS

I'm replacing injector #4 tonight.

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Wednesday, September 19th, 2007 AT 12:17 PM

14FOREST

MEMBER
9 POSTS

I replaced the injector. Still same codes. I then swapped ignition modules. Codes went from Cylinder #4 to cylinder #1. I bought a new ignition module and all the codes are now gone. Car runs great. For all you volkswagon and Audi people out there go to virtualvillage. Com and look at their Scanmax VAG reader #405. It is a life saver for $149. I bought one.