[s-cars] Misfire on 95.5 S6

[G Hicks]

A miss at idle sounds like a classic failed channel on a power output stage (pos).  They are mounted on the fire wall and once you determine which cylinder has the misfire you can do a little re-wiring to make use of the spare channel.  
Head over to Quattroworld and do a quick search.  There is a fantastic how-to to get you through the diagnostics and the re-wiring if it is in fact a failed pos.

Hope that helps.
Graham 


Sent from my iPhone

On 2013-01-23, at 6:05 PM, Alex Witham <alexander_witham at yahoo.com> wrote:

> Hi S-Heads,
>  
> I have a 1995.5 S6 with 149k with an MTM Stage 1+ chip that has a misfire and I was wondering if any of you might have experienced similar issues and know of the resolution? 
>  
> The misfire occurs at idle once the car has warmed up, but not when it's cold. It also hesitates from a standing start and mildly bucks as it misfires. Under full throttle the misfire comes in and out. Thereafter, the misfire occurs under anything from about 25% throttle ore more. Also, the problem is getting worse and worse to the point that I know have to rev the car much higher in the rev range when changing gears so that it doesn't buck as I accelerate again in the next gear from lower RPMs.
>  
> The car has a very recent timing belt, new spark plugs, and water pump.
>  
> I've replaced both ignition modules which helped for a very short while, but didn't eliminate the problem entirely and it's now back to where it was before the new modules. 
>  
> I've pulled the coil plate and watched all the spark plugs fire in sequence without a problem.
>  
> Checked for voltage at the white power plugs for the coils (sorry if I'm using the incorrect terminology) and it's as it's supposed to be.
>  
> I've tried to do an OHM test, but couldn't quite get that to work out. 
>  
> Any input would be greatly appreciated.
>  
> Thanks,
>  
> Alex 
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