Major Problem!

[tyt590]

Hi All,
I got a problem, as you can see from my earlier post I have had a SS competition exhaust fitted to my A6 and I've got to say it sounds out of this world but...... since having it fitted I am suffering from an intermitant misfire. I've took to Tweeks to be chipped and they say that the exhaust bore is not big enough and doesn't let the gasses out fast enough. Plausable but I really don't think so, sounds more like they want me to spend my money there, which is about 2 3/4 maybe 3".
I have just spent £120 on new plugs & leads and it hasn't cured it. It feels electrical so I will try swapping the coils. All this trouble started after I had the exhaust fitted, so it does make sense that it just could be but I really don't think so.
Sometimes it gets so bad that I think the car is just going to grind to a halt but if I keep the rev's at about 2500 in 3rd or 4th it seems to clear in a few hunderd yards or so and then back to normal!
It's really doing my head in so any advise will be welcomed.
Thanks for reading my whinge!

 

[Randomjim]

Is the SS exhaust de-cat? It could be something to do with the lambda sensors.

 

[maxlbrown]

I agree with Jim check the lambda and o2 sensors first.

max

 

[PlebbyChris]

Hey

Mine has the same problem. As soon as I changed the exhaust, it sounded like it started to shudder, but it isn't a misfire on mine. Mine sounds like just an extra pulse of exhaust gas and personally I think the bore theory could be possible, or maybe even just the setup. I have run the VAG.COM software several times and the engine shows up no alarms (a misfire would log several alarms). I replaced the plugs, oil, ignition coils, throttle body and MAF but it hasn't cured it.

My exhaust was a custom built stainless system that removed the mixer box from the rear so each bank of cylinders has its own exhaust pipe, but the 'misfiring' appears to be coming from both sides. I can think that it must either be exhaust system or the superchip programme I had done.

Let me know if you find any answers, I would be glad to get rid of the stuttering too.

Chris