Code was general misfire, than showed that it was in cylinder 5. I replaced the coil pack in cylindar 5 and all the spark plugs with the iridium plugs. Mind you I am no mechanic, but can do basic things....

still has the misfire...car runs great once i get to fourth gear and cruising...its just the low gears...i can really tell that i am running on 5 cylinders.

so, i said screw it...took it to my mechanic and had the timing belt changed and for him to try to fix the misfire. he tested all my coil packs and said they were good. He has diagnosed the misfire from a wire that is not generating the proper spark...causing the misfire. problem is that those bundled wires running to your coil pack have about 12 wires wrapped in that sheath...he is having a problem testing each wire and tracing them out...which he says isn't his specialty...so he had a mechanic from Bulgaria check it out and he is having difficulties as well...

Any one more mechanically inclined than myself please help! does all this make sense! I am trying to avoid going to the dealership, because they magic fix for everything little or big always starts the the magic number of $1700 plus!!!!!

Specs, Audi A6 2.7t manual six speed
128,000 miles 2nd owner
just had new spark plugs, oil change and timing belt changed
car runs like butter, except for misfire.

You need somebody who is familiar with VAG-com; monitor and log while driving.
Check the compression.
Post the results.

What would you have us do? It sounds like your mechanics are competent, have isolated the issue and are working through the problem however slowly. They need to buy an ammeter to help trace the current flows and/or a wiring diagram to find out where the little wires lead. But, what can we do to help?

Bob

I'd suggest you log 5 cylinder misfire (VAG-com).

Low gears -> misfire -at what rpm you change gears?

High gears - cruising -> no misfire - what are the rpms?

Misfire would reflect on the emissions - look for O2 sensor readings.

As per your's mechanic diagnostic performance - I'd doubt the necessity to change the TB every time a misfire is detected-> $1700 for a TB replacement looks kind of excessive.

Test the compression - carbon deposits on intake valves or in the combustion chamber (due to injector malfunctioning or valve seal leakage or etc,) then consider a fuel system purge - LubroMoly could make a miracles.
If your mechanic is not able to do the fuel purge - find one who can or do it by yourself.

Ventil Sauber , Jectron - in a 3l gas
Run for 20min, variable rpms (do not drive)

My thinking is that this sounds like an injector fault to me. I suggest getting the #5 injector and its circuit tested. The fact that it faults at low pulse widths and works fine on long ones tells me it's the injector, not the spark. I had an injector not to long ago that would not pulse at less than 6 Ms (no-load idle) but worked fine at anything above that. It was real tricky to find as testing injectors at low pulse widths is a specal test.

Great, ideas from everyone. The mechanic still seems to think its the current running from the wires to the coil pack, but with these new ideas from everyone i am going to run them by him. I don't have a prob replacing the O2 sensors...seems like after 100k, they need to be replaced anyways.

I thank everyone for these inputs and will let you know what becomes of this "situation."

I need my baby back!

Hi oldmots,

That's a beautiful XKR. Is it Black or Indigo Blue? Hard to tell from the photo. By the way, I am now both an Audi (2001 A6 Wagon) and a Jaguar (2005 S-Type) owner. I frequent the jaguarforums.com site and have added this site to my favorites so I can keep up with the various nuances and tricks of both cars.

Summary....

After replacing coil pack in cylinder 5, (which probably wasn't bad), changing spark plugs (iridium's) the problem was found by a mechanic who worked at an Exxon right up the street from house. In general conservation one day while a friend of mine was having a tire change...informed the mechanic of my misfire in cylinder 5, which no one could seem to fix. He informed me that he had fixed two A6's with a similar problem and also had the Vag-Com software installed on his analyzer. I took the car in and he called me the next day to say...just as he expected...a bad IGNITION MODULE!! He recommended that I replace both...which were $445 dollars each! Than he informed me that this is one of those parts were its actually cheaper to buy these from the dealership...where they were $195 a piece. $512 dollars later and my car is running like it just rolled off the assembly line! 126,000 miles with recent timing belt change I should be good till 200,000!

You think!

I thought I had seen you on the Jaguar Forums. I have been there for many years, owning Jaguars for a long time. The XKR is black, thanks for the nice words. Best of luck to guys who own both Audis and Jaguars. They put up with the costs to have the best design and driving experience.