Hi I'm a new user and came to this board because I'm not quite sure what's wrong with my A6.

The car is an 04 A6 2.7T s-line and the check engine light came on last night while I was in about half throttle acceleration from a stop.

The car started to shake after it came on like it was going to stall out. It shakes in park, neutral, in drive with the brake on and under any acceleration. It does not shake at a constant speed under 50mph. And it holds gears very long in drive. (I found out all of this on the way home).

I'm afraid to drive it to a local Auto Zone to read the codes from the check engine light, because I don't know if its something serious.

Does anyone know what this is from?

 

No we don't - that's the purpose of the CEL. It tells you that there are stored fault codes which can steer you to the malfunctioning part(s). Being afraid of reading them and finding out the issue won't make them go away, but remaining ignorant of the fail codes and not addressing them can lead to further failures that can be avoided if you treat the issue now.

FWIW it sounds like a misfiring problem but there's no way to know until you scan the ECU.

 

I decided to change the spark plugs and that was a PITA. I'm not afraid of what it might show when the codes are read, I'm just afraid of screwing up the car driving to the auto parts store to have them read.

Changing the spark plugs offered no help...

*edit* is it easy for these cars to have detonation? and does the 2.7T come with a forged rotating assembly or no?

 

Plugs were worth a shot, as they're easy and inexpensive. Most misfires on the A4s are caused by coil pack issues (they're known to die) and I doubt your coils are any different than the S4 coils (same motor and all), and those are more or less the same as the A4 models. Scan your codes, find out which ones you have, and post them up here - we'll help you diagnose. You shouldn't drive the car if it's misfiring actively though. Do you have a laptop? Or a desktop computer in your garage? Download VagCom from www.ross-tech.com for free, buy the interface cable off of eBay for about $20, and you can diagnose yourself.

 

I'm unsure about the cable to buy.

Should I get this one? http://cgi.ebay.com/ebaymotors/_Auto...1%7C240%3A1318

Its not for an audi A6(C6/4F), but works for an A6. I don't know if the C6/4F is the Audi I have... Its a 2004 Audi A6 2.7T S-line