[s-cars] Misfire on 95.5 S6

[Tom Green]

All this work and not one mention of any diagnostic trouble codes.   
This should be the first piece of information you obtain.

The FAQ section on the quattroworld.com UrS car forum has a lot of  
troubleshooting help.  I would certainly want the compression test  
information Dave suggests at the earliest opportunity.  Your little  
bucking with the misfire sounds like something other than just an  
ignition problem, perhaps a leak in the intake piping or vacuum system.

Tom '95 S6
          '95.5 S6 avant
Knoxville, TN


On Wednesday Jan 23, 2013, at 2:05 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