View Full Version : CEL for cylinder misfire... Already have new plugs and coils, what could it be? 4.2L

11-08-2014, 06:21 PM
Hey Guys,

Recently bought an 05 A6, 4.2L. Noticed when stepping on it that it kinda stuttered at higher RPMs, just barely. Went home, did a VCDS scan, and found the following:

Address 01: Engine Labels: REDIR FAIL!
Control Module Part Number: 4F0 910 560 A HW: 4F0 907 559
Component and/or Version: 4.2L V8/5V G 0020
Software Coding: 0007772
Work Shop Code: WSC 02325 785 00200
VCID: 204401EDF3D87B214FB-8075
3 Faults Found:

16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - - Intermittent
16691 - Cylinder 7
P0307 - 001 - Misfire Detected - Intermittent
16689 - Cylinder 5
P0305 - 001 - Misfire Detected - Intermittent

So I cleared the codes, took it out for another test run and the same thing happened, along with the same codes.
I looked at the spark plugs and the coil pack and everything looks brand new, highest revision available. Any recommendations other than the coil packs and spark plugs?

I plan to move the coil pack around to see if the misfire is following a certain plug or coil pack just incase one of those are bad, but are there any other common issues these are known for?


11-09-2014, 04:37 PM
I am also.having this issue but it got worst, there is something wrong with my fuel pump now but it all started with those codes

11-10-2014, 08:03 AM
Hmm. Interesting. How has it gotten worse?

11-11-2014, 07:03 AM
Well I have no idea if they are related first I did an oil change n filter change then spark plug change because of the codes everything was ok then a day after plug change I got this issue with fuel rail n fuel pump which another member with our car had the same issue with I have no idea if they are connected or just bad luck but it did happen to us both and I guess the HPFP is an issue with our cars and the pump also destroys the cam shaft, supposedly its a 1500 to 2500 fix which im guessing is mainly labor. But like I said I have no idea if they are connected pr bad luck but hey may as well get it checked early alot cheaper to replace if it hasnt destroyed the cam ive been.told im getting my car checked tomorrow though ill let you know what I find out.

11-11-2014, 12:01 PM
Yeah, please let me know what you find out. Seems strange that a hpfp would destroy the cams since they aren't directly connected. Wonder if it could be injectors

11-11-2014, 02:46 PM
Yeah I have no idea I was wondering the same thing but that's what a few other forums told me. Im not to aware of how the Audi systems work yet but that's what ive been told, excited but nervous to find out lol.

11-15-2014, 12:47 PM
Did you ever end up finding anything out since you took it in?

11-22-2014, 11:00 AM
sorry for the late reply I had my mechanic open her up and i Needed two new fsi fuel pumps, 2 cam followers a full tune up and a carbon cleaning, plus complete tune up. My carfax lied to me lol. but the pump problem is only on the 2.0 engines so were ok they wont destroy us.

11-23-2014, 08:22 AM
What year is your A6? 4.2L?

11-23-2014, 10:01 AM
Hmm... I have done some reading on the carbon issue and out 4.2L V8's and apperently my (40 valve) 4.2L v8 isn't an FSI engine and therefore isn't usually effected by carbon build up. But the "new (32 valve) (2007 and up) 4.2L are. So I don't think Ill have carbon build up from what I have heard.

But did that seem to help the problem you were having? Was it expensive?

11-24-2014, 01:31 PM
oh lucky you lol, and mine is a 2007, I did quite a bit of work to it though brand new plugs and coils, gaskets in the plugs due to some oil leakage in there, the fuel pumps and the cleaning but it helped my car is feeling pretty new i got all parts and labor for 2225 so a bit pricey but coulda been way worst